Scientific Inst~ ument Society

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Bulletin December No. 63 1999 Bulletin of the Scientific Instrument Society issN 0956-8271

For Table of Contents, see back cover

President Gerard Turner Vice-President Howard Dawes

Honorary Committee Stuart 1albot, Chairman Gloria Clifton, Secreta~ John Didcock, Treasurer Willem Hackmann, Editor James Stratton, Meetings Secretary Silke Ackermann Ron Bnstow Simon Cheifetz Alexander Crum-Ewmg Liba Taub Trevor Waterman

Membership and Administrative Matters The Executive Officer (Wg Cdr Geoffrey Bennett) 31 High Street Stanford in the Vale Fanngdon Tel: 01367 710223 Oxon SN7 8LH Fax: 01367 718963 e-mail: [email protected] See outside back ctnx,r for infin'mation on membership

Editorial Matters Dr. Willem D Hackmann Mu~,um of the History of Science Old Ashmolean Building Tel: 01865 277282 (office) Broad Street Fax: 01865 277288 Oxford OX1 3AZ Tel: 01608 811110 (home) e-mail: [email protected] Society's Website http://www.sts.org.uk Advertising See 'Summa~, of Advertising Services' panel elsewhere m this Bulletin. Further enquiries to the Executive Officer. Organization of Meetings Mr James Stratton I01 New Bond Street Tel: 020 7629 6602 l.xmdon WIY 0AS Fax: 020 7495 3536

Typesetting and Printing Lithoflow Ltd 26,-~ Wharfdale Road Tel: 020 7833 2344 King's Cr(~ Fax: 020 7833 8150 [a~ndon NI 9RY

Price: £6 per ~ue, including back numbers where available. (Enquiries to the Executive Officer)

The Scientific Instrument Society is Registered Chanty No. 326733

The Scientific Instrument Society 1999

..... -.qlt~ Chairman's Address 'The future is not what it used to be'

Since the fimnding of the Society in 1983 Mumum of the History of Science in this trend are already well established the strides made by the Bulletin is Cambridge, when the Mu~um was and are a pointer to future collecting immediately apparent from viewing the given well over a thousand pocket areas. Mumum selectivity will be hard full ~ries fn)m No. I to the print issue. calculators which were publicly inm~- put to keep up with the pace of change In the past seventeen years successive duced in the early 1970" and their display and pulse of scientific inh~rmation but Editors have contributed to a society generated enormous public interest. computer search techniques will enable style and content that is binding between Their everyday hmiliarity struck a chord rapid targeting of many arcane and members. From a demographic fa)int of with all generations. The fields of wire- mysterious areas. view it is inter~ting to note that whereas less, telegraphy, radio and recorded USA membership was initially a high sound in all forms, with all the 20'h 50%, the current ratio is 30% USA, 37% Looking back, the Society has achieved century advances, continue to exert Eur(~)e, 30% UK and 3% rest of the much in the seventeen years since its tremendous nostalgic lamination. In i world. founding and has bopefully set in train a sound the progression from wax cylin- tradition that future generations can refer ders, shellac 78s, vinyl LPs, and now to with real profit and insight. The thrill As the door closes on the 2(P century it is Compact Di~s and DVD mini-discs, of technological re-discovery and scien- rather tantalising to predict what recent illustrate the sheer scale and cr~tion tific principles in all their infinite variety, technology will be found collectible, for collecting in this field alone. No doubt a reassuring and constant pendulum in affordable and most important desirable. the London salesrooms will advance the our progress as pilgrims of science. An indicator occurred in 1990 whilst Jim cause of these and many other areas of Bennett was Curator of the Whipple technology, in the UK the fairs catering to Stuart Talbot, FRAS

Editorial Instruments of Science

To celebrate the last issue of the Bulletin sions of apparatus invented during the sics. ~ Rutherford characterized it as of this Millennium collectors and cura- first half of the 19~ century, and some 'the most original and wonderful instru- tors were asked which they considered to (such as the double-acting piston air ment in scientific history'. be ten key scientific instruments of the pump) go back to the second half of the last one hundred years. This has turned 18'h century. Thus, many instrument- The 20~ century devices mentioned so far out to be one of those impossible to designs had a remarkably long life and will fit into a collector's cupboard or a answer 't(mgue in cheek' conundrums. well-defined archetypes. Even new glass- museum's exhibition case, but what to do The technique of scientific instrument- and-brass instruments, such as William with the successor to Wiison's cloud making changed little over the centuries Crookes' pocket-spinthariscopeor C.T.R. chamber, the seventy-two-inch liquid until the 1940". One may certainly be Wilson's cloud chamber, had their ante- hydrogen bubble chamber completed in tempted to question the term 'scientific' cedents in the old. Crookes' instrument 1959 at the Lawn.~K'e Berkeley Labora- when putting a Renaissance astrolabe for counting the scintillations of alpha alongside an 18'h century electrical ma- tory? Many modem instruments from particles when hitting a screen of cyclotrons to solar neutrino detectors are chine or a 19'h century spectroscope, but phosphorescent material was introduced little had changed in the actual techni- huge and can only he coped with by in 1903. It consisted of a trace of radium large wealthy national institutions.Thus, ques of manufacture. At the dawn of the salt placed 1 millimetre from a small zinc the National Museum of Scotland pre- 20'h century most scientific instruments sulphide screen fixed at one end of a were still made of brass, glass, wood serves the 20-ton bubble chamber built in short brass tube; the scintillationsbeing 1963 at the Rutherford High Energy (mainly oak or mahogany) and iron. observed (and counted) through a con- Laboratory at Harwell (see this Lssue). Brass, had for centuries been the pre- vex lens at the other end of the tube (see But what should he done with even ferred metal in the construction as it this issue).So, in es.,amcewe have a small bigger instruments? What will happen, could be easily and accurately worked, for instance, to the UK's premier radio soldered, polished, engraved with scales, tube-magnifier as used for centuries in nature studies to which has been added a telescope, Jodrell Bank, when it finally and lacquered to prevent deterioration of mild radioactive source and phosphor- becomes obsolete? Perhaps the best that the surface. Their rich golden colour, can be done is to exhibit a scale mi~lel of display of technical skill, and the fact escent screen. WiLson invented his cloud chamber at the very end of the 19'h it in one of our museums. Certain],,; such that the mode of operation was obvious scientific mstallafions must fall outside in the design made them a delight for century in the Cavendish Laboratory in the scope of the private collector! collectors and instrument historians. Cambridge as a means of modelling Their journey from laboratory cupboard certain cloud phenomena. ]t harked back to collector's cupboard or museum to the 'cloud examiner' or nepheloscope The sheer size of many modem instru- exhibition case has been relatively easy. invented by the American meteorok~gist ments is not the only concern concreting James Pollard in the 18.'krP.In 1910 Wilson fmtential collectors. Another is that since constructed the version of his device the introduction of new matenals such as So at the beginning of the 20~ century linked to a photographic camera to aluminium and perspex in the postwar laboratory scientists and teachers of record the phenomena which became peri(~, most soentific instruments of the science had at their disposal a large the standard laboratory versi(m for many last fifty years or so have little aesthetic number of sophisticated and elegant years for photographing tracks of ioniz- appeal. An Eden-Rolt slip gauge com- instruments. Many were improved ver- ing radiation in subatomic particle phy- parator of 1918 with its delicate ]evers,

I~lk.tin of tl~ Scientific Imtrm.~t ~xx.t~ No. ~1 (l~) accurate to one-millionth of an inch, will 'science' - is it a methodology or a 7. mass spectrometer (Franos W. Aston, be of more interest to the collector than culture? Secondly, has an instrument got 1918 but not current until the early 1950') the infinitely more accurate 'black box' to be a unique device or can it be an laser interferometer coupled to a compu- assemblage of devices working t(~ether 8. gas-absorption chromatograph (Erika ter. towards a specific function? An electronic Cremer 1940") calculator can be seen as a scientific This bnngs us to a much less trivial instrument in which the electronics have 9. MRI (nuclear magnetic resonance ctmcern brought about by the electronic taken over the function of the mechanical imaging) (E Bloch and E. Purcell, 1952; revolution which has changed the char- componen~ of the previous generation. Mallard's prototype early 1970") acter of modern instruments more than But what about the c(nnputer which can anything el~. Up to the Second World do many things besides calculating? Is it I0. peptide synthesizer (R.B Merrifield War most instruments were anak~ue a single instrument, or is it made up of an and J.M. Stewart 1965) devices recording transient phenomena. a~semblage of discrete devices all with A typical example of the impact of their own histories? Is it perhaps more Not~: electronics (originally the thermionic apt when dealing with the 20~ century not to refer to instruments but to the valve or tube and from the 1950" For general guides, see Paolo Brenni, semiconductors) is the des,elopment of 'hardware of science'? 'Physics Instruments in the Twentieth the electrocardiagraph At the heart of Century' in John Krige and Dominique this instrument was Willem Einthoven's It could well be that the next century will string galvanometer invented in the early Pestre, eds, Science in the Twentieth see an increasing chasm between private (Harwtx~ Academic Publishers, The instrument filled two Centu~. 19(X~'. entire collectors and mu~ums. Collectors will 1997), pp. 741-757; Robert Bud and ro(~ns, had five operators and recorded continue to collect what are traditionally on phok~raphic plates the movement of Deborah Jean Warner, Instruments of regarded as classical instruments Science. An Historical Enc~lopedia Uhe the quartz string of the gah'anometer. (although the pool of these will be ]'he first dramatic change in design Science Museum , London and The continually decreasing as no new ones National Mu~um of American History, occurred in 1929 when the thermionic are being made) with inroads in post-war valve was inm~uced into the design and Smithsonian Institution in Association devices that are already becoming collec- with Garland Publishing, Inc., 1998); J. both the super delicate string galvan- tible: electronic calculators, teles'isions, ometer and the complex re(wing camera Burnett, 'The Hardware of Science' in pocket radios, transistors, video recor- Manual of Curatorship. A Guide to Mu~um could be di~arded. Many of the record- ders, and computers. Museum curators, ing instruments have been tran.sformed Practice, ed. By J.M Thompson, DA. on the other hand, will have to continue Ba~tt et a! (Oxford, 1992), pp. 374-391; in this way. As Paolo Brenni has pointed in their exhibitions to tell the story of the Maurice Daumas, Scmati~c Instruments of out in this L~sue, the miniaturisation of unfolding of science. electronic components has created an the SeTrnteenth and Eighteenth Centuries, translated by Mary Holbrook (New York: enormous arras' of apparatus that more Postscript or less look alike. Classical instruments Praeger, 1972); Anthony Turner, Early such as the recording thermometer, Scientt~c Instruments, Europe 1400-1800 Perhaps I should pick up my own barometer or hygrometer, can now all (London'• Philip Wilson. for Sotheb'sy • gauntlet and name the ten instruments be replaced by a small plastic chip sen.~r 1987); Gerard L'E Turner, Nmeteenth- that l think have transformed our Centu~ Scientific Instruments (Berkeley: cCnmected to a black box which does the century. 1 have disregarded th(~e electro- processing electronically. 'Black boxing' University of California Press; London: nic devices such as the thermionic vah'e Philip WiL~m, 19R3), Albert Van Helden has turned the traditional analogue (J.A. Fleming 1904), the cathode ray tube des'ices into digital ones. Instruments and Thomas Hankins, eds, 'Instruments', (Ferdinand Braun 1897), the cavity Osiris 9 (1994), pp. 1-250). now not truly kK)k alike but their function magnetron (1941), the transistor (Shock- Ls no longer apparent in their design. Few ley, Brattain and Bardeen 1947) and the collectors would wish to have a .seriesof microchip (Jack Kilby 1958) that form the black boxes on show labelled thermo- Announcement basic building blocks of many of the,~, meter, barometer, micrometer, etc. instruments. The dates in brackets give a Adams of Fh'et Street guide when first initiated. Many have by John Millburn Remarkable miniaturisation has al.~ spawned generations of ever more taken place in the mechanical compo- ~)phisticated des'ices. nents of in.,,truments. Coils and gears can The Committee is proud to be able to now be made ~) small that electric announce the imminent publication 1. Continuous wave wireless telegraphy of this long awaited history. The motors exist .smaller than a pinhead. (early 1900") ]he day that instrument collectors may Society has agreed to underwrite in have to examine their collections through part this important contribution to a magnifying glass may not be t(x~ far off! 2. cloud chamber detector (Wil~m 1910) one of the key London workshop in the 18'h and early 19'h centuries. Finally, in thinking about what are the 3. x-ray ~pec~)meter (Bragg 1912) Publication is anticipated in April key instruments of this century one is 2iX)0. Members will be able to obtain the b(x)k at an exclusive discounted immediately confronted by two issues. 4. cath(~e ray oscilloscope (early 19,30") Firstly, how to define the '~ientific' of price of £45 per copy. Plea~ see the "~ientific instruments', it is difficult 5. electron micn~scope (Max Knoll and flyer in this Bulletin. Thanks are due enough to formulate a definition fl)r the Ernst Ruska early 1930") to the Mu~um of the History of classical artefacts of past eras - is an Science in Oxford as keepers of the astrolabe or a sector ~ientific? For one original Miilburn manuscript for 6. digital electronic computer (John permitting publication. thing it depends on one's definition of Atanasoff, 1939)

The Trip to Russia: A Report on the 18" Scientific Instrument Symposium

This report by Peter de Clercq will be published in the March issue

2 Bulletin of the Scientific Instrument Society No. 63 (1999) Cover Story A Classic Laboratory Scene Willem Hackmann

This postcard by Ward of Manchester entering this tube at one end caused thought that he could capture a mass from the Editor's collection celebrates an sufficient ionization by collision with market with this image. Perhaps there important event that took place at the other particlesto produce a voltage 'blip' was a steady sale within the University. physics laboratory of the University of on the central wire. This was registered The publisher has captured a l~)pular experimental rig Manchester in 1908. The by the movement of the sensitiveelectro- image of how physics came to be devised by Hans Geiger (on the left)and meter shown in the centre of the perceived in the Popular imagination, Ernest Rutherford (on the right) was for apparatus pro~cting from the top. In this soon to be reinforced by the Frankenstein detecting and counting alpha particlesby manner Geiger and Rutherford could and science fiction movies. These days means of electrical methods. Up to now count between five to ten particles per these rare postcards ~fer us a glimpse of the main method had been to count the minute. Geiger was to develop this scintillations produced in Crooke's prototype into the well-known Geiger laboratory life during physics' classical spinthariscope (see this issue). The heart and Geiger-Mtiller counters. period - still small enough to be of the system was the brass cylinder (left managed by a few physicists and bud- background near Geiger). It had running It is rmt clear who the target audience gets affordable by m~ institutions. The through the centre a thin coaxial wire at was for this postcard. Rutherford had advent of 'big science' would change all high negative potential, and was filled already achieved celebrity status k~cally that. These may well be among the last with carbon dioxide at low pressure. An as a physicist. Even so it can hardly be glass and brass instruments to feature in alpha particle (or any charged particle) believed that the postcard publisher the cabinets of private collectors.

The Instruments of Applied Science

Robe Bud

What is the media idea of science: than America's. Among its key conclu- The late 1960" did see a number of cosmology, darwinism, maybe some skins was that 'Studies of the History and surveys that investigated the passage of genetics? That is 'cutting edge' science. S(~'iology of Applied Science are impor- ideas from basic science through applied The concept is reinforced by media stars tant." Yet looking at the bibliography of science into technology. This process from such disciplines for whom ideas of the history of science produced by the being found to be most c(~nnplex, and science suitably irritate the ideas of the American history of science society, in the rarely obeying the ideal tra~ctory atten- humanistically trained. And on occasion, 16 years now electnmically indexed I can tion rapidly diminished. Such investiga- of course, scientists do reach out to find hardly an article dealing with tions also proved difficult, because the discern the nature of a world, untram- applied science. study of recent applied science con- meled by human hand. ducted with commercial or security ends in mind has been impeded by .secrecy, Yet we know what a partial view of One reason for the lack of pnnninence maintained for g(K~d and understandable science this is. Science is also about given by historians to thi.,~major part of reas~ms. Thus, despite the wnportance of practice that in the last two hundred scientific enterprise is its lack of public applied science in our culture and years has been cli~ely associated with the face. Of course there L~ wide rec~,nition economy we still kra~w littlea~ut its that science had something to do with design, making and taxation of things. At practice. ]t is a particular virtue of such glamorous if destructive weapor~ a central moment of the Cold War, in instruments that they and the stones as the atomic bomb. The place of science 1967, the America's National Academy of associated with them give us tree way Sciences reported to the US House of in the more mundane aspects of practice, of recovenng an important part of the Representatives on 'Applied Science and and even war, are however often passed heritage and the family of science. Sir Technological Progress', according to over. Thus whereas there has been Richard Glazebn~k has not been for- which between 70 and 90 percent of the enormous interest in the development US' science budget was going for applied of quantum physics between the world gotten by Museum curators. His b~k is research and development. The report wars, The SCI index records not a single tm the shelves of many of my colleagues was concerned that American applied historian's citation to the Dictionary of at the Science Museum. For he was science would continue to be healthy at a Applied Physics published by the NPL interested in the underpinnings and uses time when the economies of other director Sir Richard Giazebmok in 1922- of many of the new instruments of his countries seemed to be growing faster 23, since on-line records began m 1981. time.

Bulletin of the ~'~n~ Instrun~nt ~,ty No. 63 (1999) t:ig.l Icf/~,~o,tctcr .~.IR.'t 1. ¢. l'~t,tl. ,,~ clc, tro,tas,'~:ctt, ,/t-t,l,,, Fig.2 A ,#c.lou~.tr,ltio. z,cr.,i0n i!f Gi'oGc Gh,z,i'r's ,trt/.X.cts ,m'ter I,,' m, I~tC-34 C,,urtest¢ ot.c, SPl.. mch'r, c. 18,~.-~. ~mth ,~h~ss st,fi's to show the I,clloi~,s. pMp~'s, li,k,~s','s ,rod m~'t,'rm¢, ,hfi'xes ,~e,~rm~. h,,. m,. 1887-113. C,u~rte~u of SSI'L.

[n~,truments proxide a way into the practices tt~. ]his focus takes us away telt~'ope, micn~cope (Fig. 3), and bal- constfluhon of thi~ area which gets us from the classic realm of .,,cientific ance - even if the word balance might away trom tt.xtb~k concepts of cutting- exwriment and rtx'overs the extent of .~metimt~ refer to other than instru- edge '~,Clt'nce l~ermeameters, electronic ttx'hno~'ientific practice in the 20'" cen- ments, inspection confirms that it fie- distance measur|ng devices (Fig. 1), tu~'. quently does refer to an instrument. bh,~A ga, analyzer, and skid rt~istance tt.sters have been at the cutting edge of How dot~ this affect the way we h~k at ~ence tt~r many prachtioner.~. Such a list the past? I have tried to put the Table 1 of course mcludt~, device~ that we might conventional histoq' of science literature m the perspective of the practice of not expect to include a,, scientific instru- titles ments: gas and electricih' meters for .,~'ience by using two convenient if rather including including instance, t|o~vt, ver the measurement of suspect indicators. The~, are clearly onh' Instrument Ill&me keyword partially revealing. As an indicator of I ~ 1-~tg I~1-1 July ~a,, and ehx'tricflv consumption (Fig. 2) 1~ have bet, n substantial ~ientific problems, .,~'ience I have u~'d ~'currence in the ,,talc M/,;rh(h~ fist =t ct,nducted tn a lab then, would be no titles of articles indexed by ~'ience teh',~ opt, 2~S~ I O~ mit'r, w,t'ope ~*'q36 F,O problem with identifying the~, prt~-esst~ Citation Index 1981 to I~I,1: this is accessible online. balance 1242h 42 a, s(wnhfic 1,~,'hv when in the tield should they he les~ .,~ienhfic? Mort~ver As an indicator of interest from the the n~ea~t~rt.ment of quantlt.v of gas was We art, familiar with such heroic instru- history of ~'ience community ! have u~,d hnkt'd tt~ the n~t.a,,urt.ment of its illumi- ments recognized by ~ience and history the number of occurrenct.,s as a keyword nahn~ po~er. For thal purpose Lummer ahke - the Yerkes 40-inch refracting in titles indexed by the Rt.'search Libraritm and Brodhun developed their photo- telescope; or in biochemistry - the Group. This includt.,s titles indextx| by the mett'r head in lff~q The photometer they Warburg manometer as u.,~l by Hans ttistorv of Science ~'tety, Teclmolo.~,~¢ cmd dt'xt,lopt.d would be widely u~'d in the Krebs. Culture and the Italian bibliography. (~ ph],.,io, laboratory Equally mundane course just bet'ause an instrument name wa, the origin of ~ts succe~,,,or the does not appear in the title of an article Then there are .,~me instruments that are phot,,eleclnc tube based photometer does not mean it has not been di~us~d. perhaps especially important to the who.,e earh appllcati~,n~, included pa- ~, the numbers below should be ~,en as historian of instruments rather than to per-bah, counhng and smoke monitoring. indicahve not definitive. the ~ientist. Some are no longer u.~l; lndu,tr=al, burt.aucratic and managerial others have acquired a collt~-'tor's inter- networks have mcorporatt~t instruments [tigh up in both lists are a few super t.,st, while others have built up their own ,llld mt'a~,uren3t.nt into their routine instrumenh which you might expect: literature.

Bulletin of the .~-ientific instrum,mt .%~cietv No. 63 (1~) Table 2

title~ including including Instrument name keyword IV~l-~8 lq~l-! July nanu" all artule~ hst p,mdulum [~4~ 26 a.~trolabe 87 63 quadrant not relevant 16 s, xlant ~ h ba n,meter b7 I 0

Bv contrast, there are of course instru- ments that are very important in the I practice of science which if not over- k.,ked have not received prol~wtionate interL'st from historians:

Table 3

titles including including Instrument name keyword I~I-~ 19~I-I July

llalllt' ,dl artwh'~ hst interteromvter .~)lq 3 nmr 512~7 ~,l~,clrometers/ ~l~,~-tr~,~, ~v instrt|mt,nt,~ 06~7 9

However, ] want to hx:us your attention on a third category of instrument: the enormous diverse range of instruments iml~wtant in science and its practice but Fig.3 Fnmtispiece to a tu~'lzv-pa~e wmphlet sh0wm~ a not quite in the first rank. comwund microscope by Iohn Cuff, dated September 20th, 1744 Courh~y of SSPL. Table 4 There is al.~ a relation.ship ~,tween the in the laborato~' and in mea~uremtmt el.~,where. By their dl.'sign and u.~ the,,' titles diversity of instruments and the diversity including including of scientific activities. Equally the pa~,,ing help constitute applied science. Bv h~k- Instrument name keyword over the historiography of th~e instru- ing at the history of diverse instruments I'~I-~8 l~til-Iluh' ments is a~,~ciated with a passing over one can gut an idea not lust of the sl.~' of name all artu'h'~ h~t the historiography of applit~ science. .science but al~ of its dii,ersitu ammeter 12 2 Whereas the importance of ~ientific t]oW meters 15,3 l instruments has b~x,n increasingly appre- galvan~m~,ter 22 I Acknowledgements and Note ~a.~ meter 2b 0 ciated by historians of .,~-ience,we argue gelger counter lh I that h~ds u.,~d in the construction of ! am grateful to audienct.'s at the Scwnhtic gyr~t'o[r~" 319 4 instruments central to twentieth-century micrometer 4.42 3 Instrument Commi.~,qon, ~ro Academy, scientific experiment, particularly in ap- photometer 4{~ l) D~,nmark, July |~8 and the Medical plied .science, have still heen .,~mewhat photomultipher .~,9~ 0 ~'iences Hsstorical .¢~,~'ielT, January 19'#4 i~tentlometer .~ (1 neglected by historians. Whereas the grey •,pectrophotometer 47~ ! wedge and the photomultipher have strata i~auge 421 0 been key ingredients of many deciswe I. US Nahonal Academy ot ."kwm-c~. 'Apphcd tor~,um balance 2~ 4 ~'wnce and Technological I'rL~re~,'. A R,'p,,rt voltmeter 79 2 devk'es and recur in ent~' after entry, the tO tilt" Lonlnllth'e olI .~'lelh'C ,l/hi 1.4"#r~,lhllllh-. I.l.~ wheatstone bnflge 24 0 words 'photometer' and "photomulti- th,use of Rcspr¢,~'nhltlP¢~ (Washington IX. plier' are not to be found in the Re~,arch 1~7~ p. 22 It is to this last category that l want to Libraries Group's History of Science and Technology Databa.~' of titles since 1976. attract your attention. It expresses the Author's ~,ln's.~: diversity of forms of the scientific th~ad t!? Re~'arch ~Colh'~tums) instrument that perhaps we have a Such devices are equally the result of ~'U'nce Mu.~'u m special rt~ponsibili.ty to record. scientific effort and equally are used both London SW7 21)D

Bulk,tin of the ."k-wntificl~trun~,nt ~.. No. 63 (199q) The Van de Graaf Generator An Electrostatic Machine for the 20 t" Century Paolo Brenni

Foreword Cataloguing these instruments will ai.~, apparatus smmgly marked several dec- create a series of problems. [k,cause of ades of contemporary science and found A few months ago, the editor of the their complexity it is unthinkable to application in various fields of physics, Bulh'tin asked me to give him my descnbe them in the same detailed way astrophysics, and medicine as well as in per.,~mal list of the '10 most iml~rtant we are used to with an ancient micro- various mdustri~. Second, it derived instruments' of the 2(P century. ! asked scope or with a quadrant. Who made form a series of more ancient u~tru- h~r a few days of reflectitm. Some t~me what? That is another very difficult ments. Third, it is useful and I~)pular in pas~l but instead of having compiled a question for the historian of 20'h century schwa)Is and exhibitions as demonstrati(m rea.,amable list of apparatus, my doubts science. If we admit that a signed Sho~ device. Fourth, depending on its use, size and my hesitations had grown. Identi~'- telescope was made by the very famous and power it can be considered a mg the most significant scientific instru- English instrument maker of" the 18'h 'classical" instrument (as a demonstrati(m ments up to the beginning of the 20'" centurv, and if we agree that a signed electn~tatic machine) as well as a typical century seemed clear enough, but rank- Ram:,~en ~xtant was at least manufac- artefact of 'big .science'2 Therefore the mg the apparatus invented since then tured in Ramsden's worLshop (even if Van de Graaf generator can be consid- was more troublesome. Ram~|en him~,lf perhaps never touched ered a gtx~d example of emblematic 20~ it), what will we be able to say about an century apparatus. Most 2(P century scientific instruments electronic apparatus? Today the brand are incomparably more complex than the name on it does not mean much as far as Introduction ones of the previous centuries. A defini- production is ctmcerned. We all know tion of them more preci~ than 'the that many electronic instruments can be The Van de Graaf electn~staticgenerator hardware of science 'j is almost impossi- ag~embk~l in Korea, using microchips is an 'addition' electn,static machine: ble. Is a transistor or a magnetron a manufactured in the United States, charges are added to a conductor by a scientific mstrun'~,nt? Tbev are, but they electrical components coming from movable carrier. In its simplest and al.,a~ are elements of more complicated Spain, Taiwan or Germany, and finally schematic form this apparatus is com- scientific instruments. So in the list of the sold under a British brand name. The p('~ of a motor-driven verticalendless- "10 best of the 20"' century' should I problem with the apparatus of big band (made of rubber, rubberL,~,d fabric, include the magne~m or radar (wh(~e science, which are often comp(~d of paper or another flexible insulating electromagnetic waves are generated by tens of thousands of elements made by material) stres,,~'dbetween two rollers. the magnetron itselfl, or both ? And what hundreds of different firms is even The lower part of the band is electrically about the computer? is it a scientific worse. Does it make sen.~ to speak of a charged by a brush or comb, which is in.~trument or not? Yes and no. Compu- maker or manufacturer anymore? Prob- connected to a directhigh-tension source. ters (alm~ coml~ed of thou~nds of ably less and less. Can we really speak of (In the smallest didactical generators the instruments) are u.,~ed for laboratory instruments or do we now have to speak belt is simply charged by a small friction re,arch and thus they can be weil of instrumental systems? pad.) The charges, which can be negative considered instruments, I~ut they are al.~) or positive depending on the source, are omnipresent in the domestic'environ- As you can see, my previous text is full of carried bv the pulley to a spherical ment. In this last case is a computer a question marks, which correspond to hollow elt~ctrode which is installed at ~-wntific instrument? if ~, then must we open questions. Nevertheless, if my heart the top of the machine. Here, the charges alm~ accept the hi-fi stereo and the kitchen (and certainly those of many readers of are transferredfrom the belt to the sphere microwave oven as ~cientific instru- the Bulb,tin) is more attracted by the by a second brush or comb. Electric ments? My pm,~entation of the pr~hlem glitter of old fashioned 'brass and gla~' charges accumulate on the external sur- is perhaps paradoxical but certainly is than by the c(n~lness of contemporary face of a conductor and thus the potential not really far from the realitv. 'aluminium and plexy', it is extremely of the sphere is limited only by the important at the end of this century to corona effect and by the dielectric A Renaissance astrolabe, an 18"~ centu~, ~riouslv begin to think of its irt~tru- constant of the surrounding medium. vacuum pump, or a .,~,phisticated 19'" mental heritage. Finally, and I will return The maximum electric tension, which in centu~' spectroscope, are self-contained to this point in the closing remark of this the first large air-insulated machines and easily recogni~ble instruments. The)' article, a large part of this heritage risks could reach a few million volts against have a well-defined archetype, which being scrapped. But if we want to study, the earth, is a function of the diameter of (hke in the ca~ of the astrolabe) could unde~tand, and, when it is possible, to the spherical conductor. last for several centuries.: The miniatur- preserve the material witnesses of 2(P i.,,ation of electronic components created century scientific enterprise, we must try The Van de Graaf generah)r, which was an enormous arras' of apparatus, which to give some answers to the above developed from the end of the 1920 and more or le~s kn)ks all the .same. Unlike the mentioned questions. And that will became immediately very ~)pular, de- ca~, of a 19'" century spectroscopes, their probably be possible only by modifying rives from a series 18m century electro- exterior design is not distinctive anymore in many cases our meth(~lological ap- static machines. and it d~ not at all determine their u~ proach to historical scientific instru- and their function. An inch square plastic ments. ! think it is an important and The Ancestors of the Van de Graaf chip is the .,,en~w, which, peri(~icallv exciting challenge. Machine conntelectrostatic generator can be found in conceal an amplifier, a pulse generator, a ments of the 20'h century, at least ! have the second half of 18'h century.' In 1784, photometer, a signal analy.~r, etc. and so ch(~en to retrace the history of one of Walckiers de St.Amand constructed such it is even difficult to understand from them: the Van de Graaf generator. Several a machine with an horizontal looped silk their k,)k what the,,' are. rea~ms guided my choice. Fi~t, this strip passing over two wooden milers.

Bulletin of the Scientific Instrunent ~k,~ty No. 63 (1999) I"

Fig.1 Late 18 'h century R,,uhmd's endless-band electrostatic machine. From Gehler, op. cit. note 8. the silk was rubbed by two sets uf cushions fixed near the rollers. The prime conductor, where the charges accumu- lated, had two series of collecting points Fig.2 R~hi's "electrometer'. Colh'ction (!f the Fonda:ione Sctenza e and was suspended centrally between Tecnica, Florence. the kx~ped strip of silk. Walckiers also made a very large machine with a silk in fact a Perfect miniature Van de Graaf strip 1.5 meters wide and 7.6 meters long. pulley. Continuing their journey the rings generator ante litteram. However, this enter a hollow insulated copper sphere, This generator was successfully used at machine had not been conceived by his the Aca,K'mie Royale of Paris and an where they touch a third small metallic inventor as a generator but as a 'charge pulley fixed on its inside. Thus the improved version (Fig. 1)' of it was than magnifier' for investigating weak electro- charges of the rings accumulate on the constructed by the physicist Rouland static phenomena. With it, Righi wanted external surface of the sphere. As the (active in the 1770" and 1780"), who was to investigate 'Volta's effect' and measure process continues the charges are con- the nephew and collaborator of the the weak potentials developed by the tinually added to the sphere. It is evident famous experimentalist Jean Ren~ Sigaud contact of different metals, hence the that this machine works in the same wav de Lafond (1740-1810). But this machine name 'electrtnneter'. as the Van de Graaf apparatus. Several tix~k up too much space and at the end of Righi's apparatus were manufactured in the 1780, the German Gottlieb Christian Italy and can still be seen in various Bohnenberger (1732-1807)% the inventor The idea of increasing an electric charge, coll'ections ~ but the idea was not devel- of a well-known electroscope, proposed a which is too small to be measured, was oped for over 50 years. (Even if at the end new version of the machine with the belt not new. in 1786 Abraham Bennet (1750- of 19'h century John Gray, an electro- set in a vertical position. In 1809 the 1799) and in 1788 William Nicholson (1753-1815) had prop~z~-.d their 'multi- technician who wn,te a famous treatim French physicist Claude Veau Delaunay al~ut electrostatic generah~r, prol~ed a (1755-1826) illustrated in his physics pliers'. These apparatus, which in fact were induction electrostatic machines, rubber band induction machine which treatise: the Walckiers' machine. Veau was more complicated than the Righi's Delaunay admitted that this apparatus represented fundamentally a mechani,~M version of Volta's perpetual electro- ones), in 1893, Bush proposal an end- was very little used, because it was less-belt machine. Between the k~ped generally too big and not very nice phorus of 1775."' With these apparatus very small charges, to weak to be belt of paper, rotating on two metallic kx)king ('..son aspect est Peu agreable.'). cylinders, there was a unusual s-shar~ed Nevertheless he thought that it could be detected by a common electrometer, were 'multiplied' by electrostatic induction ttx~ted collector, which was connected to improved, and profitably used in various the prime conductor. But Bush's machine public institutions such as schixds and until they could be measured. Righi was working in the ,'~me direction when he was simply a smaller and lmpro~.ed hospitals, following the suggestions of version of Rouland's generator, which the physician Louis Caullet de Vaumor~ prolx "~'d his machine, which is in fact an adder and not a multiplier, u was sup~,i to be a demonstration (1743-?), who like Bohnenberger had apparatus.'* L)t.,spite .~me minor mod- prop("~ed an endless-band vertical ma- ifications the endless-belt machines were chine, in 1827 Walckiers' machine was Righi's apparatus is extremely simple, t: never really popular and they could again illustrated and described in Geh- A rubber belt carrying a largenumber of never compete with the disk induction ler's Physikalisches Worterbuch and even bra~,~ rings rotates on two metallic pull- generators of Holtz, l-oepler, Vies, Carte, later in 1876 it was mentioned by E. eys. The lower one, which is insulated, is Wimshurst, Wommel.,~.iorff and others Mamart as an historical curiosity. ~ Un- connected with a crank, the upper one is fortunately no endk~s-band machine of grounded with a copper strip. Ckz~e to the time seems to survive. the belt, in the neighL~mrhot~ of the The Race to High Voltages upper pulley, there is a small metallic In 1872 the young physicist Augusto conductor (the inductor) which Ls con- In 1917 the British physicist Ernest Righi (1850-1920)" of Bologna in his nected to the weakly charged t~iect to be Rutherford (1871-1937) transfo~| ni- PhD thesis described an 'induction elec- studied. The inductor charges one after tn)gen atoms into oxygen by bombarding trometer' (Fig. 2). This apparatus not one another the brass rings of the belt them with alpha particles generated by a only used a kx~ped flexible ring but was which pass on the upper grounded radi(mctive isotope. ]'he transmutation of

Bulletin of the Scientific Instrument St~iety No. b3 (1~) F~g.3 l,m ,1," t;~,;,It ,h',n,m,tt,ltm),, Oth" ot 11i5 early ,~cnenttor. Pn,perty of the Mas~l- cllusett, Institute of Technolok,}t. [ elements, the mythical realm of alche- mlsb,, was, at fea~,t on a micro.,,copic .,cale, becoming a reality. But atom .~ma.~hing rtNuire, very t~igh energit.,s. Natural radit~ctwe element~ .,uch as the very expen.,qve radmm art, .,,ourct.~ of particles (alpha, ek~.'trons, as well as gamma raw,) but their energy and their U ~ ~ LJ L~ L~ CJ LA numix, r art' t(n, low tor penetrating the potenhal barrier (the Coulomb wall) of Fig.4 t)nm,.t X of tit; lain de Gnlaf xenenth~r at Round Hill ~South the nuclei of heavier e]ements. By the l)armouth, Mass.I. From Hedl,nm, SeMel, op. cit. note 14. 1'420- it appeared.| evident that further mveMigatmg of atomic and nuclear at the Carnegie In.~titution in Washing- property,-, ~ould reqmre more energetic ton In England, Ciwkcroft and Walton, and ,nten~qve _,,treams of accelerated who, in 1932, achieved the first successful parhcle,,. Charged particles could be disintegration of nuclei bv electrically obtained m d,tferent ways+ Gas dis- accelerated particles used a voltage chargt~, could pnMuce ions, while for multiplier with a complicated array of electron~, ~t wa~, po.,,,qble to u~t, hot wire .,,witche~ and conden,,ers? ~ Re.,~mance eml~,-,,on or other ~,v.,,tem,, lhe energy (E) transformers, transformer rectifier and ot a part~cle in an electric tMd corres- all manner of other apparatus were pond, to the product ot it.', charge (q) te~ted. Certainh,', one of the N~t ideas tim,.',, the tern, Ion (U)of the field: E = q .U. wa~ developed [w Robert Jami~n Van de [hu~,, a tir,,t po~,,ible ,.olution of the Graaf, who chl~e to develop an old problem ~a~ e-,.-~'ntiallv to accelerate fa~,hioned-style electrostatic machine. Fi- the part~cle,, m a vacuum tube to which nalh', others (such as Lawrence with his a ~er~ h~gh ~oltage win, applied. /he cycl~trons) ch~n~e a completely different nMhon-volt race had began, and it was way: the particles could be accelerated in nghtl) ..,tared that: The tu.~Zll-ten,nUl a,,el- ~,(eral steps using moderate electric crdtor. .tn'tched the power of Illsllldtor~ tlltd fields. But that is another sto~'. t/h' tl('l"~'("., lit" l~tl~l~,lCl~,t to brt'd~itl~' poillt. ~' .'~'~ eral ~wtem~ were prop~,,~t. The Invention and Evolution of the Van Fig.5 Spectacular art(ficial lixhtnmk, pro- de Gram Generator '~ &wed In¢ tit," Van de Graaf y,enerator at lhe German~, Bra,,ch, I.ange and Urban R,,un,t Hill. Pr,,perty of the Mas~chusetts tried to u~' the atnm~,phenc ehx'tricitv of lhe American physicist Robert Jamison instituh, of Techn,,h,,.?!l. hghtning, before turning to more prac- Van de Gram was born in Alabama in tical and le~,', hazardou~ impulse (,,r 19t11. After having received a masters ~urge) generator Fht"-,e kind of impul~, degree in mechanical engineer in Alaba- later he received a D.Phil. in physics. In generatoP, were u~'d by elt~ctrical en- ma, he moved to Paris where he attended 1929 Van de Graaf joined Princeton gmeer~ for te~tmg elo:trical equipment. the courses of Marie Curie at La University as a National Research Fellow in I'~.~1 a very powerful oil-insulated Sorbonne Unive~itv.'" In 1925 he went and at the end of the same years he built h',da coil wa,, t~uilt for the same purl~, to Oxford Universit'y, where, three yea~ the first model (Fig. 3) of his generator

Bulletin of tl~, Scientific Instrument ~wildy No, 6.3 (19~9) Fig.7 Brnm't's early tandenl accelerator. II1 the centre ~ the appanttus there is the hi~,,h i'olta~e cylindrical electn~fi' u,lth thc.~ul stripper. Fnmt Rose, Witthm,er, op. tit. note 25.

had to be subshtuted, but, due to the Fig.6 /)rawm~,. qt th,' I/an dc t;ntat ~,,em'nltor ~!t til,' I'al,.5 ,fi' la shortage and the critical wartime situa- Di;cauz,erte in Paris. fn~m Maul. I.P., Le Pahlis de hi D¢;couz,erh, tion, nothing could be done. lherefore, ¢Paris, 1994L this spectacular Van de Gram was never used for any ~ientific research and it was finally ~rapped. (80 kVolt). Soon the apparatus was installed in the Thom,~m Theatre of impnwed and, in November 1931, he Electricity of the museum, were it is In 1935 Van de Graaf received a patent demonstrated for the fi~t time a new, regularly demonstrated. for his inx-ention and he continued to inexpensive and much more powerful work in the field of electrostatic gen- machine (about 1-1,5 MVolt) at the [h,fore further retracing the development erators, logether with his collaborator, inaugural dinner of the American In- of the Van de Graaf generator, it is here John G. [rump, pn~f~,~r of ekvtncal stitute of Physics.'" Van de Graaf joined worth mentioning another very large engineering at MIT, he was involved in then the Massachusetts Ttx'hnologica[ machine of this first type (doubJe, non- the construction of such apparatus for Institute (MIT) as a research as~)ciate pressurised). During the 1937 Paris pr¢~iucing highly penetrating X-rays for and in 1931 he began to construct a large Universal Exhibition, an impressive Van both mcxtical and industrial purposes. double generator in an unused dirigible de Graaf (Fig. ~,) was installed in the During World War II, Van de Graaf was shed at Round Hill (~uth Dartmouth, newly opened Palais ,fi" In D,;c,u,z,erte, director of the High Voltage Radio- Mass.) It consisted of two 23-fl,~t high which was (and still is) located in the graphic Prolect, where he deveh,ped insulating columns each containing two Gramt Palais. = This apparatus, built by A. electrostatic generators for the radio- belts and supporting an alummium Lazard under the direction of the famous graphic equipment of the U.S Navv. Atter sphere, 6 feet in diameter (Fig. 4) . [he French physicist Fr¢~.teric Joliot (1900- the war, Van de Graaf and [rump columns were mounted on railway 195I% was supp~~d to be u~,~-~d after fi~unded the High Voltage Engineering trucks .~ that the distance between them the exhibition as a powerful ~urce of Corlm~ration (HVEC), which became one could I~, easily mi~tified. This impressive radiolelements. This machine was com- of the most ~mportant manufacturers of machine, which was widely featured in p~l of two Van de Graaf generators elecm~static generators fi~r cancer ther- technical journals and popular maga- accumulating charges of different polar- apy, industrial radiography and rt~eareh zines of the time (Fig. 5), was functional ity at a total tension of 5 Mvolt. l-he in high.~.nergy physics in November 1933. It was claimed that it generators were 14 metres high and could produce 7 million volts but in fact mounted on rails. The spheres at the In the late 19~" Van de (;raat invented the it developed about 5 MevY Two small top of them had a diameter of 3 metres. insulating core transh~rmer which pro- iaboratork,,s were located in the spheres, Each generator had three independent duced high voltage dwect current exploit- where scientists could study the effect in endlt.~s-belts driven by ,,.eparate motors mg magnetic flux instead of ehx-tn~,tatlc the accelerating tube which would have and charged bv a 10,000 volts direct chargt.'s. With his collaborators at the connected the two domes. Due to the current ,,~mrce. :I-he system was entireh' HVEC, he also successfully developed difficulties of mounting the discharge ench~.axl in a gigantic Faradav's cage. the technology of the tandem generator tube between the spherical terminals this This machine, which amazed visitors to (,,~ee below). Van de (;raat remained generator was never satisfactory as an the fair with its spark several metres long as,,~ciate profes.~r of physics at MIT until accelerator. It was subsequently" moved was on the front-page of many maga- 1900 and then he dedicated his actBlh' to to MIT, where it was completely mt~- zines, but had unfi~rtunatelv a ~d fate. the HVEC. Besides ~eral honorary ified-" and u.~,cl fi)r atom smashing and I~,cau~ of World War II it was forgotten degrees, in 1906 the Amencan Physical high-energy X-rays research. Finally in in the Palms de la t~;couzvrte and only in ~'ieO,' awarded him the T.l~mnerpnze the 1950" it was donated to the Ek~ston 1942 was it I~vssible to undertake its fi~r his contributions to the development Museum of Science. In 1980, this gen- removal to the Joliot's laborato~ in Yvrv of electrostatic accelerators. Van de Graaf erator, which is probably the iargt.'st near Paris. The machine had to b'e dio~'] in 1967. At that time over ~10 particle surviving machine of this type, was overhauled and a few mechanical pieces accelerators of his ~'pe were in use.

Bolletin of the %-wntific Instrument ~'ieW No. 63 (Ib'~9) Charge-changing, Tandem-principle and Tandem generators

But apart of a series of very important technical improvements, the discovery of the charge-changing effect, led to the realisation of the ~ called tandem. generators, which largely improved the performances and increased the fields in which the Van de Graaf machine was u~'~l, z" The principle of this type of machine was independently proposed in the USA and in Germany .~ IV m in 1929 Bergen Davis (1869-1968) and Arthur Barnes at Columbia University had discovered that it was p(vxsible to electrically neutralise the [n,sitive charges Fig.8 Th,"tandem acceh'rah~r ,~ lCalllnum and Kuhn. In the centre of the apparatus there is the hi~,h ~,olta~e cylindrical ehvtn~te and ¢,a~ alpha particles by attaching electrons to stripl~'r. Fn,m: Weiss, op. cir. note 27. them. This fact opened the possibility of obtaining high energy by carrying these neutralisecl particles to a charged term- In the 1930" the use of Van de Graaf vacuum techniques, negative ion beam inal and then, after having taken away generator spread rapidly, and their first, formation, a corona triode controller, an the electrons, to accelerate them to V,'pical design changed very quickly. It is electrostatic charging system and other ground voltage and to repeat the process impossible to mention here al'l the devices. In 1965 he fi,unded the Na- again. The first experiments were un- technical findings, which contributed to tional Electrostatics Corporation (NEC), successful but they attracted the attention mcrea~ the perfiwmances and the relia- which is still today one of the leading of Van de Graaf. The discovery of bility of these machines. Studies on high firms for the construction of Van de negative ions2~ led WiUard H. Bennet voltage and on insulators, the reali~tion (1903-1987) in 1937 to propose a patent of better materials and special mechan- Graaf generators and ancillary equip- for an accelerator exploiting the charge- ical elements certainly boosted the pro- ment. Among the most interesting changing effect. In his apparatus (Fig. 7) gre~ in the construction of electrostatic innovations prop(~-,d by Herb and his accelerators. collaborator there is the Pelletron. This is negative ions were accelerated to a thin fundamentally a Van de Graaf machine, metallic foil ([n,sitively charged), where the electrons were removed. The resul- Several fundamental improvements and in which the rubberized-fabric endless modifications were suggested bv the belt L~ replaced by a special chain (or by tant positive ions were finally accelerated to a grounded target with an tmergy American physicist and industrialist more of them) of metal pellets connected which corresp(naded to the one acquired Raymond Herb (1908-1996).:~ In 1931 by insulating nylon links (Fig. 10). In Herb began his works with accelerators 1947 Herb and his group had put staples in a 'classical' accelerator with twice the voltage. But at the time negative ions at the University of Wi~onsin-Madison. m a standard endles~belt to increase were rare, and Bennet's idea was s, mn In 1933, together with a few collabora- voltage stability. This idea was devel- forgotten. tors, he prol~-,d one of the yen, first oped fiw several years and finally at the pressunsed Van de Gram generators, u end of the 1950" and in the 1960" it was It is certainly less well known that the This m(~lification proved highly success- possible to find a good solution using a ful and was further devehCped and principle of the tandem-accelerator was "stnng of beads' charge carrier, which also di~overed and derek,peal in Ger- universalls' adopted. All Van de Gram evolved into the modem Pelletron (Fig. machines" for re.arch and industrial many by Harmut Kallmann (1896-1978), ll). The chain (which is curiously who had been an assistant and colla- purposes came to be enclosed in a reminiscent of Righi's rubber nng with (vertical or horizontal) cylindrical or borator of the famous scientist Fritz the bra~s carriers) has several advan- Haber (1868-1934) z, In the 1930" Kal- cigar-shaped pressure tank, a departure tages compared to the Van de Graaf belt, from the t~ pical column-and-sphere de- mann, together with his collaborator which is subject, for example to spark sihm. Electrostatic generators were be- Kuhn, were trying to improve a charge- coming more and more ~,phisticatecl. damages. The metal pellets of the chain change experimental accelerating va- are charged and discharged by induc- cuum tube (a m(giified 'Kanalstrhalen' in the following .,,'ears with his colla- tion (like many late 19" century gen- tube) proposed by Christian Gerthsen borators at the Univer.,,itv of Wisconsin, erators) and no sparking and corona (1894-1956). In 1938 Kalmann and Kuhn Herb developed ...,everal pieces of equip- effects are involved in the process. Not patented ~ an apparatus, which was quite ment for the Van de Graaf generators. In only has it a longer life, but also it is similar to the one of Bennett. This device 1~35 he propo.~d the first column also insensitive to moisture and gives (Fig. 8) produced i:a,sitive ions, trans- enchv~,txt by ch~,ely ,,,paced metal nngs excellent w)ltage stability Today most formed them into negative ones, and (equipotent'ial rings), which contributed powerful Pelletnm chain generators can accelerated them into a positively to pna:luce evenly distributed voltage deliver current of l(10-2(]0 t~A and the charged tube electrocle. The gas mole- ,,,tress. in 1940 he'and his collaborators potential terminal can go up to 25-30 cules flowing in the electrode changed by introduced the use of three concentric MVolt. :~ A different type of charging shocks the polarity of the ions, which, high potential electn,dt.,s. During World chain called Laddertron, was devek)ped with a positive charge, were repelled by War II Herb joined the Radiation by the HVEC. The name derives from the electr(~le, thus being accelerated Laborato~, where he worked on radar the fact that the this chain had originally again. Kaimann and Kuhn tested their system but, unfortunately because of and atter 1945 continued his work with H shaped metallic carriers, which k~)ked the accelerators, deveh,ping ultrahigh like a ]adder. political reasons, which after 1933 forced the Kaiser Wilhelm Institute to a more

IO Bulletin of the Scientific Instrument Society No. 63 (1999) ~.~ ....,'" "'~%'i~ ',~' :; ..,:,.~ ..... ~,, ~,,o,..~.,

;. " c., (~ .ql=f r(~=~ e. (,,~G ;Cry[

..... ,..i.~...~.44111L ---- , ,, -- Z.~I~LIIIlll.II! G~IIII~,.... ---'c_~_.~,,,,, , ' \ t I I --7-- " \7; / tL~j / / / [_L__]~ \

Fig.9 Sclwme ,!f a tandem ¼m de Gnlaf Ne¢ati~v ions enter into the accelerator from the left side. From R~', Wittkou~,r, op. cit. n0te 25. " " Fig.lO A ~ction ~ a Pelh'tn,n char~mg chain with a pull~. From the Pelletron u~@ site, see m~te 25.

utilitarian and war-oriented activity, the stage designs with two Van de Graaf in tron and X-rays production, ion German discovery of the tandem princi- line one after another, are also used." implantation, polymerization, diagnostic ple did not produce any important The folded tandem design is constructed measurements, etc.) application and was mainly forgotten like a single stage vertical generator by the history of science. with tree column containing two parallel accelerating tubes. One of them accel- A Less Successtul Type of Machine Based on the Van de Graft Generator A few years later, in 1951, the physicist erates negative ions from ground ~ten- Louis W. Alvarez (1911-1988) , who did tial to the high-terminal voltage not know Bennet's nor Kalmann's work, terminal; while the other accelerates One of the most curk,us, through not built a small charge-changing accelerator, ~sitive ions from the terminal down really successful, modification of the Van showing the practical feasibility of such a to the ground potential. de Graaf generator had been c(~ceived system. Also in the 1950", Van de Graaf around 19.36 in France by M.Pauthenier, and the HVEC finally developed a very professor of physics at La Sorl:xmne in Tandem generak~rs proved extre- succt.'ssful machine of this type which to be Paris, and his collaborator, Mrs. Moreau- mely efficient and reliable and they are became known as the tandem-accelerator Hanot. u In fact, the,,' proFK~ed to use a utilised m several research and indus- or tandem-Van de Graaf. The first flow of charged dust particles circulahng trial laboratories around the world. Van practical machine of this type was in a ck~-'d insulating pipe instead of the de Gram machines, especially the ones constructed by the HVEC fiw the Chalk classical I~qt of the original apparatus. used in high energy physical research, River Laboratory of the Canadian Atomic The dust was composed of glass spheres Energy Agency. can be very large. The most I~werful of a few microns in diameter. A blower ones, such as the French Vivitron ~' or produced a 60 m.p.s flow of these certain types of tandem Pelletrons can particles in the ka~p-pipe. For charging Tandem-accelerators machines are en- reach a voltage of about .30 Mvolt. the dust there was a 'i,mi~r', which was cl(~! in high-pressurised tanks (Fig. Vertical generators are usually installed coml~ "~ed by several wires parallel to the 9). The voltage is generated by an in specially built towers. Furthermore, pipe. The wires were negatively charged endless-belt which is in a column (or m(dem Van de Graaf generators are (12,0~X) volts) by a kenotrtm ro~tifier and horizontal tube) with equipotential nngs much more sophisticated than the ones the electric fielcls of the wires i(~is~:l the whose open terminals are grounded built in the 19~'. Ion sources, particle gas molecules. ]he i~.~sttive ions were while the cylindrical collector in the in~ction and particle beam handling, immediately attracted by the wires, while middle of the column is brought to a vacuum (for the accelerating tube) and negative ones were repelled in the high voltage (we imagine +) by the pressure equipment (for the tank), con- direction of the walls of the pipe and charges carried by the belt. Negative tml and measurement instruments, etc., charged the dust particles. Great care had ions produced by an appropriate source form a very complex array of apparatus to be taken for adjusting the various are accelerated in a vacuum tube inside typical of 'big science' equipment, for parameters (diameter and speed of the the cylinder and in correspondence to which the interchange of ideas between particles, voltage of the wire, diameter of the high voltage terminal they charge is scientist and engineers proved to be the ionising tube) so that the dust did not changed by a gas or a metal foil particularly fruitful. In spite of the fact precipitate on the wall of the tube but 'stripper'. So, the now positive ions are that other type of machines (syncrotrons, could continue its journey after having repelled by the positive terminal and cyclotron, etc.) can accelerate particles to been charged. At the top b~nd of the pipe leave the accelerator with an energy much higher energy, electrostatic accel- the charged dust entered in a kind of witch is double of that achieved with a erators, which are very versatile and centrifugal collector, which was con-" single-stage Van de Graaf of the same present great beam uniformity, lower nected with the spherical terminal elec- voltage. This is an example of a well cost, are ideal for many applications. trode of the generator. In the collector the defined charge-changing (negative-posi- The largest one are used for basic charges of the particle were transferred to tive) schemes but several others are research (or as in~,ctors for other kind the electrode. At the Paris Universal l~)ssible (positive-negative; positive-neu- of accelerators), while the smaller ma- Exhibition of 1937, together with the tral, neutral-negative, etc.) and multi- chines are employed in industry (neu- above mentioned large Van de Graaf, it

Bulk,tin of the Scientific Iru~trument Stwiety No. 63 (lqqq) I1 ones, which become respectively nt~a- [ 1 tively and positively charged.

Final Remark

A final I:n~int has to be considered as far as large 20m century instruments are concernt~. How many chances do they have to survive as material witnesses of the history of science and technology? Not many, I fear. The case of Van the Graaf generators is emblematic. As 1 mentioned above, at least one large historical Van de Graaf of the 1930" is prt~,rved in a museum, where it attracts visitors with its spectacular high voltage phenomena. Small machines of this type u~ for didactic purl~vses art, extremely common in the physics collectinns of educational institutions, and many of them will probably survive. But what about the large research generators built after World War ii? In 199& after 38 years of service at the Nuclear Astrophysics and Material Science communities, the Caltec EN Tandem Accellerator facility had been ck "~-~d. The accelerator wa~s destroyed : Not puttin~ it t,~, delicateh/: the Fig.ll Drawm~ ottlw 12 MVolt Pelletnm acceh'n~tor built in 19"76 machine was r,x'ently cut up and .~,id fi,r at the Tsukuh~ Unit,ers~ty qapanJ. Fnun q I,r~+hure t!f the Natmnal scrap. ~ It is true that, machines of this Eh',trostatws C,,rl,on~ta,n. ~'pe are extremely difficult to preserve. They are very. large and heavy and they was p~y~s~bleto ..~'e a Pauthenier-Moreau- Van de Graaf in the Boston Museum of often occupy several hundred square Hanot generator capable of producing a Science wrote: metre iatn~ratories. They are not particu- voltage of about 1.8 Mvolt, working with larly attractive: from the outside m,~ern a flow of minute glass spheres. ]-hough The D~pular apwal of .,uch gigantic gen- Van de Graaf generators knN like big oil this ingenious apparatus ra|.,~d a certain erator has I~,t,n tremendous. It is an aw,~ tanks. Often they cannot be dismantled enthusiasm, it was never widely u.,~x] inspiring experience to stand beneath the without being destroyed. It is difficult and remained a curiosity. huge .spher¢.,s and feel the hair rise as and certainly far t,n~ expensive and potential lncreasecl, and then to ~.t, the long complicated to keep them running just lagged strokes of man-made lightning as for didactic or historical purp~s and, The Van de Graaf Machine as Didactic terminal dischargt~ to the n~f or down the Apparatus furthermore, they do not prcKluce any column. ; particularly impressive phenomenon. In fact, m~Klern Van de Graaf, in spite of the If the \an de Graaf generator continues So h~av eve D' ~htn~l laboratory as well fact that they can generate tensinns of to have a brilliant career in the field of as many mu~ums u~ these generators several millions volts, are not sup~Ysed Iligh energy physics, astrophysics and in for the most spectacular electrostatic to pr~nJuce sparks! Finally museums are ,~'veral industrial applications as re- demonstrations. In fact, a few didactic not very keen to store this kind of .,~,arch and proft~ional apparatus, in apparatus machines were developed equipment, which requires an enormous It,, simplest form it al~ proves to be recenth,' on the principle of the Van de amount of space and which hardly can extremely popular as didactic instru- Graaf generator with ~me m,Klification become an attractive exhibit. Of course it ment. IS.,cau.,,e of its solidity, of its concerning the system of carrying the is much easier preserve documents such ,mlple conqruction, and of its in.,~.nsi- charges or transferring them to the belt. as photographs, films, videt~s, plans and tlvflv to a~r m,usture, the Van de Graaf Most of these generators can reach a drawings related to an apparatus, but the cm ~ts basw and primitive design) wdtage in the range of 10-1(N) kVolt and artefact itself has g~K~d chances to be became an ideal demonstration appara- art' used for demonstration purpo.+~.s. ~4 scrapped. How much would we know tu,,, oxershadowmg most of the old- Among them we can mention the atnmt astrolabes if we had only written fash~,u~t,d and complicated electrostatic ingenious generator conceived by the descriptions, engravings or images of mtluence machine. Furthermore, for physicist Gabriel Loriente in Madrid. '~ them? Certainly much less than we know didactic purpo~e~ it is much simpler to Lorients's machine has four parallel t~nJay. explain the functionin~ of a Van de rotating rollers with their surfaces kept (;raaf than one of the classical induction in contact by means of springs. The two Of cour.~ not all contemporary science Ls ('influence') mach,nes. ()n the other internal rollers are respectively made of 'big science' and still many apparatus can hand, men have alwavs been fascinated teflon and nylon, while the external trees be 'collectible' which do not create t(m by lightning, big sparks, and effluvia of art, made of metal. Teflon and nylon many difficulties, but preservation of corona etfect,,, therefore the.'~' machines ~:cup)' opposite places in the 'electr~- large equipment will prt~ent in the very ahvaw, made for an ideal and very static .~,ries' and due to their contact, the near future a series of problems. On the appr~.'ciated display at imp,~rtant exhibi- former receives electrons from latter. The other hand, if a large number of 'classical, tions, S~lence IllUseums and science charges on the surfaces of the insulating ancient' instruments were rescued and centres I,ivmgston contemplating the rollers art, transferred to the metallic preserved by private collectors, who

12 Bulk.tin of the Scientific Instrur~,nt ~bcieW No. 63 (]~) played and still play today an essential VIII, 1872, pp. 123-134; Luscia, pp. 184-186 and 23. See:. Graw-Hdl Modern Sca,ntist and En- role in the survival of artefacts, it is hard A. Righi, 'Sur le pnneipe de Volta', Journal de xmee~s (New York, 1980), vol. I!, pp 4445 and to imagine that they will be able to do the physique th~orlque et appliqu&, 3 (1874), pp. 19- G.A. Norton, J.A Ferry, EE Daniel, GM. same as far as late 20 ¢" century big 23. Righi also pn~,,¢l a different version of Kk~dy, 'A Retrospective of the Career of Ray apparatus are concerned. his machine. Herb', in Heaz~. Ion Accelerator Technol~Ry: E#gth international Conference (edited by K.W She- 13. See, for example, the collection of the pard) 1999, pp. 3-2.'*. I am very grateful to Dr Will the furore instrument historians be Museo di Fisica of the University of Ikdogna or the collection of Fondazione Seienza • G.A.NoMOn for providing me with much forced to work without historical instru- the useful information about R.Herb and the NEC. ments as the most important sources of Tecnica in Rorence. their research? It is a serious risk, which, I 14. See H.W. Sehmidt, 'Elektnsmschinen 24. The breakdown voltage in insulating gas believe, we have to begin to consider at and Apparate', m Handbuch der Elektrizititt und varies with the type of gas and its pressun,. the dawn of the third Millennium. Macnetismus, VOl. 1, L. Graetz, ed. (Leipzig, Several gases such as CCh and CCI2F 2 were 1918), pp. 21-93. used m the elecm~static tank generator. Today the most used msulahng gas is SF~ (sulphur Notes and References 15 See J.L. Heilhron, R.W. Seidel, Lawrence hexafltanide). and his Laboratory. A History of Lau,rence 1. This definition was given by John Bumett. Berkel~ Laboratory, Vol. i (Berkeley, 1909), pp. 25. See" http-//www.peiletron.c(nn and R.G See J. Bumett, The Hardu~re of Science, in 4F,-71. Herb, 'Pelletron Acceleratms for Very High 'Manual of Curatorship. A Guide to Mu~um Voltage', Nuclear Instruments and Meth(cis, 122 Practice', ed. hy Thompson JM., Bas,~ DA 16. Their apparatus was, in fact, m~t new. The (1974), pp. 267-276. and others, Oxford, 19~2 (II edition), pp. 374- Swiss physicist Heinrich Greinacher had 391. pmpos(,d this kind of voltage multiplier in 26. See P.H. R(r,oe, A.B Wittkower, 'Tandem 1919. Van de Graaf Accelerakws', Scient!fic American, 2. About scmntific instrument archetype, 223 (197{)), pp. 24-33 and R Van de Graaf, Anna Van Helden recently presented a very 17. The Van de Graaf generator was aLso 'Tandem Electrostahc Acceleratms', in Pmceed- interesting paper at the XIX Scwnhfic Instru- mention as statitnmin the past. m~ of the 1958 Accelerator Conference, Cam- ment Symposium (September 1999). 18. See Dictama~. af Scwntlfic Ba.~Irapha,s; Mc bridge, Mass. (High Voltage Engineering Corporation, 1958). 3. It is emblematic that a rock music band, Craw-Hill Modern Scwntists amt En¢ineers (New which was quite famous a k,,w year ago, was York, 1980), vol. 3, pp. 245-246; E.A. Burnll, 27. Negahve tons is pn~uced by coupling an called 'Van the Graaf Generator'. 'Van de Graaf, the Man and His Accelerators', external electron to a neutral atom. Physics 7hlay, 1967, pp. 49-52; PH. Rose, 'In 4. 1 just mention the machines that used a memoriam: Robert Jamison Van de Graaf', 28. See B. Weiss, "Hochste Spannung Fritz moving band, and ! do not include hem the Nuclear Instruraents and Methods, 60 (1968), pp. Haber, Harmut Kallmann and das "Tandem- fabric drum generators. See for a more detailed !-3. Prinzip". Ein hubes Kapitel des Beschleuniger- description W. Hackmann, Electricity from Geschichte', Kultur & Technak, ! (1997), pp. 42- Glass (Alphen aan den Rain, 1978), pp. 140- 19. J. Van de Graaf, 'A 1,500,000 Volt 49. 142 and the related bibliography. Electn~static Generator', Physics Re~,iew (1931), pp. 1919-1920. 29. German patent 6q¢¢~8, 9 February, 19,~ 5. Rouland, Descnphon des machines electrost- tatiques d ta.ffetas (Amsterdam, 1785). 20 See for example the h'~mt page of Scwnttfic 30. It is impossible to mentum here the Anwncan and the rulated article t~ Nikola Tesla cmnpk~e bibliography concerning tandem- 6. He has m~t to be ctmfused with Johann (am)ther pkmeer of high-voltage techradogy) generators, lher~ore see the ahwe menhlmecl Gotflieb Bohnenberger (1765-1831), who pro- on this machine" "R~bilities ol Electr~Stahc references. Fa)sed the gold leaf elecmmx~r with two Generators', Sclent!hc Aria'titan, 19M, pp. 132- Zambini dry cells. 1.34 and 16gl6~. Tesla staled : I behe~¢ that 31. The Vivltron Is a large (~)-metre k~ng when new types [of Van de Graaf generators] are tank) tandem Van de Graaf built m Stra..~urg 7. C. Veau Delaunay, Manuel d'electricitd which was installed in the I~P. For a (Paris, 1809), pp. 14-16 dewk~d and sufficio#lu ~mpre~ed a ¢,reaffuture will be assured to them. See aLso L.C. Van Atta.0 description see http://sbgall0.in2p3fr/tms/ 8. J.S.T.Gehler, Phus~kali~hesW~terbuch, I[[ D.L. Northrup, C.M. Van Atta, R.J. Van de recherche / vivitron/descnptU~n.html. Band (Leipzig 1827), pp. 4~-456 and E. Graaf., 'The Design, Operah~m, and Ix-~or- 32. See B Kwal, M Lesage, 'Les ires hautcs Mascart, Trait~ d'electricitdstatique (Paris, mance of the Round Hill Elec~static Gen- tensams (qecmques par les pou,~an~s char- 1876), vol. I, p. 249. The machine is also erator', Ph~ical Ra,ia~; 1936, pp. 701-776. One gees. Le gen~ateur Unuque de M Pauthemer illustrated in W. Nichol~m, 'Ill. Bemerkung of the best historical survey on the devek~p- et cle Mine. Moreau-HamW, La Nature, 1937, I und Versuche, die Electricit;it betreHend', ment of Van de Graat generators and of others semester, pp. 147-151. Gilbert Annalen der Physik,23 (184)6),pp. 272- type of accelerators can be found in: S.M. 312. Livingston, J.P. Blewett, Particle Acceleratm's 33. See Livmgton 0p. clt. n~e 19, pages 32-33 (New Y(wk, 1962), pp. 30-72. The hiblk*graphy 9. Augusto Righi, became famous for his concerning electn~tatic accelerator is so large 34. See fl~r example the machine at the fundamental research on the properties of that we can just suggest here some interesting universi~ of Nantes: http://www.~tenc~. electromagnetic waves, which extended and contnbutams. Several interesting pictunes of univ-nantes.fr/ physique/en~ignement / tp / refined the first observations made by Hein- the large Van de Graaf can be seen at: http:// wimshurst. rich Hertz. Furthermore, Righi invented several apparatus. Amtmg them a three-sparLs www.mos.org/sin / toe/ctaxstructum.html and 35. 1 am very grateful to Dr. G.la~nente for oscillator, which was used in the very first http://www.mos.org/sin/toe/history.html. A the mhwmati~m he sent me omcemmg his very intenesting site ctmcerning Van de Graaf wireless expenments of Marconi, whi~ had machine. His generator was patented in lq~ql generators is pr~xr-~ed by Lyt~l Baum. to followed some of the Righi's lessons at the in the USA (N. 4.~1813) and later in the University of Bok~gna. wfu~m I am grateful for much useful infta~na- Eurt~:~ean Unkm iN. :~6r~qll). See http:// ~m:http: / / members.aol.com / lyonelh info.uned .es/electrostatic-generator / 10. See J. Gray, Les machines ilectnques index.html. influence (Paris, 1892), pp. 161-163 and F. 21. The machine, which was encic6ed in a metal dome was tran~dormed into an uni-polar Luscia, La tecnol~ia delle macchin¢ elettrostatiche 36. R)r an account of the demohti~m of such a (Brescia, 1928), pp. 88-98. generators. The two spheres were joined together In one of the colunu~ were left the machine see http://www.itscaltechedu/ -arice/tandemhtml II. In an 'adder' the charges are accumulated charging belts, while in the other the accel- in anthmetical pmgresskm, while in a 'multi- erating vacuum tube was installed. Author ~ address plier (such as the Thomson 'replenisher') the fondazame Scienza • Tecnica charges increase in geometrical pmgressitm. 22. A. Lazard, 'Le Palais de la D~-ouverte scienfifique. Le grand g~n~rateur tsleet~x~tat- Via Giusti ,27 12. A. Righi,_'Descrizkme di un elettrometro tique/~ 5 millions de volts', La sca'nce et la Vie, 50121 Florence ad induzione°, il Num~a Cimento, Serie !1, VII- 51 (1937), pp. 279-284. ltal~

Bulletin of the Scientific ~t Society No. 63 (IVY) 13 Ten 20 th Century Instruments at The Smithsonian in Washington, D.C.

Introduction

Deh,rah I. War,er

The Smithsonian lnstitutilm was estab- hshed in 1846 with a bequest from James Smith.,~m, an English scientist, mandat- ing an institution located in Washington, D.C. and dedicated to the increa~ and diffusi~m of knowledge among men. The inslatution has grown rapidly, and now encompa.,,~,,~es numerous museums and research facilities. Its funds t~dav come %,.., chiefly from the federal treasu~,, i,-upple- merited with .~me pnvate donations.

J,~'ph Heno; the first Secreta~' of the Fig.1 Rabi's ".,~,uz,enir'. Fig.2 Linedrau,m~ ~. Rabi~ magnet. Smith.~nian, hoped to devote the re- sources of the new Institution to ~ientific research. As it happened, however, !.1. Rabi's 'Souvenir' of His Career in tion of this slice is a supl~ "vsed cutting Congress ~w the Smith.~mian as a fitting Molecular Beam Research (1937} apart of that indium magnet, at some repository for the anthropological and unknown time, in order to create a pair of other natural histoo' specimens that were Paul Forman magnets as required by the magnetic coming into Washington from across the resonance technique. United States and around the world. The Pairs of deflecting magnets with inho- technological and historical collections mogeneous fields produced by pole Thus, the indium magnet is not only the that came to the Sm,th,~mian during the pieces of semi-circular cross-section were prototype for the magnets of Rabi's earl',' years included a few notable almost universally u.,wd in the decade N(d:~el-Prize-winning resonance method, hist~'~" of ~ience objects, such as an following World War II, as the molecular it was also the culmination of the a~,~wtment of stuff from Joseph Priest- beam magnetic resonance technique for programme that Rabi had pursued lev's home in Northumberland, Pennsyl- preci~ measurement of the magnetic through the preceding seven years to vania. But the maior history of science moments of atomic nuclei, originated by measure (then, before magnetic reso- effort at the Smith.~mian b~egan in the I.I. Rabi and collaborators at Columbia nance, by an indirect method, without 19~'50-, at a time when the histo~" of University late in 1937, came to be the atom making a transiti(m between ~ience was gaming a p(vsition in Amer- practiced'al~ in many other physical energy states) the spirm and magnetic ican universities. M¢~t of thi~ apparatus research laboratones. Indeed, that pole moments of nuclei. For his purpose Rabi is hou.,~d in the National Museum of piece configuration, with an iron core of had conceived a magnetic deflecting field American History (founded in 1963 as C-shaped cnvss-section, had been em- wh(vse strength at every, i~)int (and hence the National Museum of History and ployed in all of Rabi's prewar molecular its action Ul~m atomic magnetic mo- Technology). It is ~attered among such beam magnetic refinance expenments, ments) could be known by calculation, collections as Physical Sciences, Electri- experiments Performed with at least two for accurately mapping of the magnetic city and Modern Physics, Medical different apparatus using several differ- field on so fine a scale was hardly Sci~:nces, Biological Sciences and Infor- ent magnets. Such generality, of use itself feasible, it was the field produced by mation Technology. Other history of gives sigmficance to this magnet, fi~und two parallel wires carrying equal but science collections are found in the in Rabi's office following his death opposite currents. And that's just what National Air and Space Museum across (Fig. l). It had evidently been prepared Rabi used until the 300 amperes that the Mall. and held as a .,~)uvenir. (Only so is the Columbia's bank of batteries could relatively crude hinge holding the two supply was just not enough. To achieve ~,~,hile the Smith~mian has ~me wonder- halves together to be explained.) In use, higher fields, Rabi designed an iron ful m~truments made and u~,~'d el.,~~- this magnet would have st~n~ with the magnet to produce the same field where, .,,uch as the circular dividing gap vertical, at top, as in the drawing. configuration. This proved remarkably engine built by JL'~.,,eRam.,~:len in London But what distinction recommended pro- simple geometrically - semicircles - but in the 1770", and an Islamic celestial gh~he motion of this particular magnet to no small feat to machine with high made m Lahore in the earl',' 17'h centu~; ~uvenir status? precision over a metre's length. In this our fiwus today is on obiects made and/ department, however, physics at Colum- or u.,,ed in the'Unito:l Statt.'s. Thus, each The line drawing showing a magnet of bia was exceptionally well provided for, in.~trument di~:u~,wed here is American. ve~' similar cnms section (Fig. 2) was and Rabi's work always had priority. .%,loreo~er, reflecting our various collect- published in Rabi and collaborators' Thus this one artefact, even as fragment, mg practices, tht~, instruments range rt~rt on their experiments, Performed embodies a great part of Rabi's career from one-of-a-kind devic~ designed fiw during spring and summer 1937, to and achievement as physicist, and con- ,l~'~'clfic e×|~,riments, to commercial pro- determine the magnetic moment of the sequently has high qualifications as duct,, designl~| for practical purl~,~s or indium nucleus. Al~ the CheSS-Sectional souvenir. the delight of amateurs. Finally, while dimensions, as stated in that re~rt and .,~me early collections arrived" at the as measured on the artefact, agree. Object: Natkmal Mu~um of American .~mith~nian w~th minimal supporting Although ,~me inconsistencies do stand History Accession No. 1996.0331. Gift of d~-umentation, current practice involves in the way much evidence supports the the Estate of l.I. Rabi, 1989. capturing technical details and informa- identification of this souvenir as a 'slice' tion about the contexts in which the off the metre-long magnet described in Literature: E Forman, 'Researching Ra- obiecb, were made and u~'d that report. The occasion for the produc- bi's Relics: Molecular Beams and Nuclear

14 Bullehn of the Scientific Instrument ~'iety No. 63 (1~) Magnetic Moments before Magnetic Re- sonance, 1927-1937,' Artefact, 2 (1999), in press. Sidney Millman, 'Recollections of a Rabi Student of the Early Years in the Molecular Beam Laboratory,' Tran~lctions ~. " the New York A(ad. of Scu'nces, 38 (1977), pp. 87-105. Norman E Ram~y, Molecuh~r Pn'ams (Oxford University Press, 19%; reprinted 1990), pp. ,399-400, 431-432.

The ENIAC Computer (1943-46)

David Alli~m

The ENIAC ranks among the most significant artifacts in the Smithsonian's National Mu~um of American History. ENIAC was built by a team of engineers at the Moore ,School at the University of Pennsyh,ania between May 1943 and February, 1946 (Fig. 3) . The team was working under contract for the Ballistics Fig.3 ENIAC computer at the Unnwsity of Pennsyh~nia. Research Laboratory of the U.S. Army Ordnance Department. The name EN- IAC is an acronym of 'Electronic methods was announced t(~lay by the War torians claim, however, as Mauchly Department .... This machine Ls the first all- him~lf did, that if he and Eckert got Numerical Integrator and Computer'. electronic general purp(~ie computer ever anything from Atanasoff's work, its Principal engineers on the prowd were developed It L~ capable of ~dving many J. Presper Eckert and John W. Mauchly. technical and scit~ntific problems .~) complex significance was of limited importance When complete, ENIAC filled a room and difficult that all prevmus meth(ds of to the success of the pr(~-,ct, in large part, measuring 30 feet by 50 feet and solution were considered impractical .... this is becau~ the genius of ENIAC weighed ~) tons. It used around 18,000 ik,gun in 1943 at the request of the Ordnance derived more from the brilliance of its vacuum tubes of 16 types, 1,=~0 relays, L)epartment to break a mathematical I~ttle- engineering than its fundamental con- 70,000 resistors, and 10,000 capacitors. It neck in balli.,.tic research, its peacehme uses ceptual design. was 8 feet high, 3 feet wide, almost 100 extend to all branches of scientific and engineering work: feet long (if stretched out), and con- sumed 140 kilowatts of power. Con- Like most important technologies, the struction costs were around half a The claim, voiced here, that ENIAC was electronic digital computer uihmatelv million dollars.' the 'first all-electronic general purp<~;e derived from many sources and the work computer...' has been a source of con- of many People. Besides contnbutionfi The Army commissioned ENIAC to troversy ever since. Much of the debate made in the Umted States, iml:n~rtant perform a specific function: computing has centered on patent L~ues. To sum- developments were also made in Europe ballistics tables for aiming Army artillery. marize a complicated story, Eckert and before and during World War II. Many Creating accurate tables was a laborious Mauchly belatedly filed a patent applica- people in addition to th,~e invoh'ed m process of ~dving differential equations tion based on ENIAC in June 1947. They the patent fight made iml~)rtant con- hw hundreds of positions and configura- finally received a patent m 1964. The tnbutions to the evolution of the digital tions for each gun. When the ENIAC claims in their patent were broad, and computer. These included pioneers such project was started, human 'computers' ~n Sperry Rand, the company with as George Stibitz at Bell Latnwatories, (largely women) were performing the which Eckert and Mauchlv were working Howard Aitken at Harvard University, calculations by hand with mechanical by this time, began seeking infringement Konrad Zu~ m German,,', and others' calculators, and they were falling hope- fees. Sperry Rand ~,ttled privately with lessly behind ~hedule. If the operations IBM, but another target, Honeywell, could be done in a pre-programmed challenged the patent. After a detailed ENIAC remains singularly iml~rtant, sequence by an electronic machine, not investigation and trial, Judge Earl Law- however, because it marks a major only would they be completed faster, but son invalidated the ENIAC patent m late trart, iition, it sto(~ at the beginning of results should include fewer errors than 1972. In part he ruled that crucial the digital computer industry' in the hand calculation. elements of ENIAC derived from prior United States. No machine before ENIAC work by John V. Atanasoff, an inventor was as large or I~.~wefful. None had its By the time ENIAC was finished, the war who had built a special-purpose electro- technical sophistication. Befo~ d, no was over, and the original goal was no nic computer at Iowa State College in the companies were striving to create and longer a pressing matter. All along, late 1930". Although Aianasoff's machine .,,ell electronic digital computers as a however, the development team realized never worked well and he ultimately principal hne of business. ENIAC proved that what they were creating in ENIAC dropped the priwct, John Mauchlv had that a general-purp(~e electronic compu- known and visited him, and arguab'ly got was much more than a special purl~e ter was both p,~,~lble and valuabk,. Alter some ideas from this connection. ~ calculating device. An Army press re- the War, and largely because of ENIAC, lease announcing its creation in 1946 the field of digital computers was open proclaimed boldly: The ruling by Judge Lawson has been ENIAC was a clear, public announce- taken by some to be pnx)f that Atanasoff ment that the digital electronic computer A new machine that is expected to revolu- was the 'Father of the Computer' and had arrived, and that the Federal tionize the mathematics of engineenng and that Eckert and Mauchlv were of sub- Government was strongly ,~upl~rting its change many of our industrial design sidiary iml~)rtance? M(~t computer his- development.

Bulletin of the Sc=entific Instrument %~clety No. b3 (1~) 15 In retrospect, ENIAC L~ remembered infornultion Age: People, Infl~rmation and (1996): pp. 17-24; Letter, John H. Magru- almost sok'ly as a turning point. Eckert Technolo,c,y. AI.~ included are segments of der to Col. Raymond C. Gall, Chief, and Mauchly s(~m went mt to start their a video history interview with Presper Historical Services Diviskm, Office of own computer c¢nnpany and build new Eckert conducted in 1988, in which he the Chief of Military History, July 8, and better machines. Indeed, they had explains aspects of how ENIAC worked. 1965, Accession Folder for ENIAC, Divi- begun designing their sec(md computer, Nearby are artefacts and stories of earlier sion of Information Technology and EDVAC ('Electronic Di~rete Variable computer developments, including work Society, National Museum of American Arithmetic Computer'), even before EN- by Atana.~ff, Stibitz, Aitken, and others. History. IAC was complete, becau~ they s~'m saw how limited its capabilities were. Obiect: Additkmal parts of the Smith.~- Electromagnetic Cavity in which ENIAC was es,,~ntiallv a large, program- nian holdings are tm display at the M~,re Nuclear Magnetic Resonance was First mable calculator, not a true stored- Schl~l at the University of Pennsylvania, Observed in Condensed Matter (1945) pn~ram computer, as EDVAC and later and the Heinz Nixdorf Museum in computers were to be. Paderbom, Germany. Ih.,sides the compo- Prod Forman nents at the Smith.,amian, additional Even as the field moved beyond ENIAC, pieces of ENIAC are held by the Late in 1937 l.l.Rabi and collaborators at the US Army c(mtinued k, run it for University of Michigan, The Computer Columbia University ob~rved nuclear almost a decade - first at the University Mu~um, the Bradbury Science Mu,,~,um magnetic refinance in a molecular beam, of Pennsylvania, and then at the Aberd- in I.x~s Alamos, and the US Arm,,'. Other acting on the su~estion of Cornelius een Proving Ground it was finally pieces are still in private hands. Gorier, Leiden, who had tried but failed turned off in (~-tober 1955. The firs! ~o ob~rve the phenomenon in solid problems ENIAC soh'ed were not ballis- Seeing physical remnants of ENIAC materials. In the following three years tic table calculations, but calculations makes a difference. Its tubes, wires, Rabi's lal~)ratory pr(~uced a stream of related to the design of a hydrogen panels, and relays give viewers a ck,ar astonishingly preci~ measurements of bomb." Sub.,~'quent calculations dkt re- .sense of the I~istorical difficulty of nuclear magnetic moments by this tech- late to ballistics tables, but al~ nuclear creating a digital computer in the 1940". nique. By 1945 the NMR concept was weapons effects, wind tunnel design, Smith~mian visitors, impres:,~l by EN- much in the air, especially in Cambridge, probabili~" distnbuti~ms, weather fore- IAC's physical size and scope, are awed where Rabi, five years as deputy director casting problems, and man,," other to- when they realize that it could do but a of the MIT Radiati(m Laboratory, sur- pics/ fraction (~f the work of today's desktop rounded by many of his students, machines. Viewing ENIAC in historical celebrated the receipt of a Nobel Prize A major advancement h~r ENIAC came context also helps them understand the late in 1944 for that prewar work. in lq4K when Army engineers modified circumstanees that brought it into being, it so that it did not have to be and that have fostered the development In the autumn of 1945 Edward Purcell, a programmed by replugging wires and of computers ever since. The further we young Harvard physicist who had been cables ('d|rect programming'), but in- retreat from this milestone, the more lent for the duration to the Rad Lab and .,,tead could be programmed using stored significant it becomes as a major turning was then stillengaged at MITm writing instructions in the form of a 'converter point of the 20~ century. up the results of his years of work on code'. This extended its useful life by radar, again conceived the idea of allowing it to work as a rudimentary Literature: Michael R. Williams, A His- detecting nuclear magnetic resonance in stored program computer. It was clearly tory ~ Coml,uti,R Technolo~u(Englewln~d solid matter. The obvious person to .~mething that had not been originall.~, Cliffs, NJ: Prentice-Hall, 1985), p. 276; US consult about the feasibility of such an intended During the c~q,, anniversary War Department, Press Relea~ 'Ord- experiment was theoretical physicist celebration of ENIAC at the Universi~' nance [h'partment Develops All Purpose Henry Torrey. Torrey had earlier done of Pennsvk'ania in lqqO, computer scien- Calculating Machine', dated February 15, an experimental dissertation with Rabi tists simulated the machine in m(~lem 1946, available in the National Mu~um and worked through the war in the Rad hardware and documented significant of American Histor); Division of Infor- Lab's microwave components group. a.~pects of its ~tructure. They concluded, mation Technology and SocieO,,or on the There Torrey shared an office and 'the basic hardware units of the ENIAC World Wide Web at http://www.si.edu/ worked most closely with Robert V. were d~.~ign~l to provide the function- re,'~)urce/tours/comphist/ pr l.pd f; Scott Pound, the then stillquite junior, electro- alitv of a very large electronic adding McCartney, ENIAC: The Triumphs and nically gifted, Harvard physicist. machine, but it was clearly not designed Tra,o'di~ of the World's First Contputer to m~p]ement what a mta.tem computer (New York: Walker and Company, Torrey's immediate reaction, like Rabi's ~-ienti.~t would recognize as a computer." 1999); Clark Mollenhoff, Atana.q~.: For- when told of the proposal, was, naturally, ¢,otten Father ~ the Computer (Ames, iowa: sceptical. But a calculation of the antieip- ]he Smlth~mian owns most of what is Iowa State University Press, 198~); See, able ab.~,rption of ek,ctromagnetic radia- left of ENIAC. This includes over 2(1 among others, Paui E. Ceruzzi, The tion having the same frequency as that of panels, two function tables, i~wer sup- Rech,ners: The Prehist,,~. ,¢ the Digital the precession of hydrogen nuclei (pro- plie~, fans, and many small components. Computer, From Relays to the Stored tons) in a rea,,~mable magnetic field - [he oblects in ~ts collection were trans- Prox, ram Conc,7,t, 193.5-1945 (Westport, ab~,rption due to the slightly larger ferred to the institution by the Lh,part- CT: Greenwo(~ Press, 1983); W. Barkley number of protons having their spins ment of the Army in 196~5, following Fritz, 'ENIAC - A Problem Solver', IEEE and magnetic moments oriented with deliberations that [~ad I~,gun as earl,.' as Amnds ,¢ the Histo~ c~ G,mputm~, 16:1 than against the applied magnetic field 1957. They were to be included in a (1994): pp 25-45; Fritz, 'Appendix A' for - showed the effect to be detectable. But di~,play ai a 'National Armed Forces a complete list of ENIAC applications, if so, 'why did Cawter fail?' Thus in Mu~.um', to ~how an ;ml~)rtant Army Mitchell Marcus and Atsushi Akera, developing an experimental protocol 'first' in the history of technology. ~ That 'Exploring the Architecture of an Early Purcell, Torrey, and Pound were pre- mu~,um was never built, but h~lay, most Machine: The Historical Relevance of the occupied with the l~)tentialbut incalcul- of the Sm;th~nian's ENIAC components EN[AC Machine Architecture', IEEE able pitfalls they supposed to have are indeecl ¢m exhibit in the display, Annals ~ the Histo~ ~¢ Computm~, 18:1. defeated (~)rter: rapid saturation and,

16 Bulletin of the .'~'lentificInstrun~,nt ~ciety No. 63 (1999) especially, slow relaxation In fact, neither phenomenon p~ed a problem Once the three had gotten past a less creditable mi~alculation of the field of the large electromagnet of which they made use, nuclear magnetic rt.'sonance of protons was ob~,~'ed with surprising ea~ on December 15, 1945. For l'urcell - just as hw Rabi - a Nobel Prize followed exactly ,~,ven years after.

]'hat ek~ctromagnet, earlier constructed h~r Cur O' Street's cloud chamber ob- .,~,rvations of c~,mic rays, was located in a shed beside Harvard's Lyman Physics Laborato~'. i'his determined the locale of the experiment. New pole pieces were fashioned to reduce the field diameter to 6 inches (15 cm), and increase its strength, with a gap of 3% inches (9 cm), to almost l0 kilogauss. The coaxial cavity, of these dimensions, was Fig.4 Purcell~ electromagnetic cavity. fabricated of brass, with copper central conductor, by Pound's Rad Lab techni- Yet it has been regarded as a milestone m reflected by one of two mirrors h~ a cian, Charles Rowe. it is pictured here astronomical history. Rowland grating, which both dispersed (Fig. 4) upside down (as ai.~, of course, the light and focu.~d it onto a 35-mm cut away, and sub~quently refilled with Indeed, as one might expect fiw anything strip of spectr~copic film. paraffin in such a way as to reveal the made to obwer~'e the sun from a spinning input and output coupling loop/coil). and gyrating ballistic missile that was Under (actually; over) the uncut di~ - bound to crash in the deserts of White The spectrograph was designed, tested which is .,~'parated by a narrow gap from Sands, New Mexico, this was a very. and flown by a team of Navy physicists the cylindrical sid¢~ of the cavity - there special spectrograph (Fig. 5). A roughly and engineers led by Richard Tou~,~. a is a thin layer of mica insulation comcal structure 60 cm high and 30 cm at former student of the vacuum ultraviolet .,,eparating that di~ from the (here cut- its base, the spectrograph was con- spectr~,~copist Theodore Lyman at Har- away) bottom (top). This heavy capaci- structed of thick welded steel parts. vard, and a man who knew his way tative loading was rt~quired to render the Two parallel circular metal plates are around the laboratory. Tou~y, as a Naval cavity recreant at the precession fre- mounted at the ba~ of a rectangular I~x Research Laboratory ,,~ection head, col- quency of protons in the available hou.,,ing the optics. These supl~rt mo- lected I:~,ople who knew optics and magnetic field, i.e., about ~) megahertz. tors, timers and gearing to advance the se~'o-systems, especially tire-control de- In.,~,rted in an rf bridge circuit, the cavity film and store it in an armoured steel vices that had to survive harsh working showed its reduced transmittance at cas~,tte. It was extremely ruggtM, shaped environments. The Navv's goals and resonance by unbalancing the bridge, like the warhead of the missile becau~ it mi,,,sion are prt~,rved inthe artefact. It and this produced, after several instru- was originally design to fit at the tip of was not built to solve astrophysical mental stages, a rectified current through the warhead, veto' compact, and able to a microammeter. collect ultraviolet" .,~lar radiation from a very wide .~did angle. 1-o ~v the least, it Object: National Mt,seum of American was unlike any spectrograph ever built History Accession No. 281,295. Gift of by an astronomer, and it was one that an E.M. I;urcell and RV. I'ound, 196q. astronomer would not likely build.

Literature: Robert V. Pound, 'From Radar Fir.,,t, it lacked a prowr entrance, which to Magnetic Rt~,nance', Revu'u,s of Mt~t- had been standard practice among crn Phi/sits, 71, no. 2 (Centena~' 199q), physicists and astronomers h~r a centuo', pp. S.~1-551,l. R~ert Buderi, The Invention in order to i~flate ab.,~rption and emis- that C/mn~ed the World (New York: Simon sion features with a maximum degrt~, of and Schuster, 1996), pp. 266-272, 508419. fidelity. Second, it lacked any methl~ of photometric calibration to determine line V-2 Spectrograph (1946) intensiti¢.,s. Third, it had very low dis- persive [n~wer, so it could onlY,' .~,n.,~, the David DeVorkm gros~est featurt.,s of the .~flar continuum and its line stnJcture. Two troy 3-mm The instrument that .~cured the first spherical lithium flunnde beads acted as spectrum of the sun in the far ultraviolet, entrance apertur~.,s for sunlight. Not only beyond the limit forever blocked by the did they catch sunlight over a very wide, ozone in the earth's atm~sphere, was a angle, but also their extremely sho~ fi~'al spectrograph flown on a captured Ger- lengths creatt~| an inten~' ~int of light man V-2 missile in Och~er 1946. This that approximated a slit as the missile was the realization of a dream of many gyrated. No matter where the missile astnmome~. But no astronomer had a was pointt~l, one of the two apertures hand in the production of this spectrum would be in sunlight. This light was then Fig.5 V-2 Stwctr,~rat,h

Bulk,tin of tl~, .%,'ientifi¢ Instrument .%~'ieW No 63 (1~) 17 que,,hons but gt~t+physKal ont.'s, ques- hons that were of dirt~.-t x'alue to the Naxx t~xau~, they could inform ballis- tics ~,tudms and Itmg-range communica- tions, .~xstems development. What was the ozom, dens~tv profile in the upl~,r atmo~pl~,re, and what part of the .,~+lar spectrum caused the ionosphere to change? ttow dtm.,s one build a .~+phisti- cated mtx'hanical device to fiX' on a rt~ket, hnk it by telemetry to report on ~ts status duringflight, and return data of u~' to the Navv? Tht~t, were the typ~.,s of qut~,tions the ruggtM I'ou~v spoctro- graph could tackle and thaithe Navv Fig.0 I.d,l,us c,u+,t,'r h,r r, atlo-ool,on Fig7 17w ~mw cou.ter, asa'mbh.d would gladly pay for, not only in 11h'll~llrt'fFh'II~+;,+ dl~1>~'.lbh'd+ ct~peratmg w~th Arm,,' Ordnance in the bring of V-2 mi.,,siles at White Sands, but Mounted tnMde the middle third of this I'hvsics Cat. No. N-l,,t7q. Gift of Dr. W. E m the development and maintenance of larger cylinder, ~upporttxt from one end I.ibbv, accessioned ~'ptember Iq, 1%1. new torms of .'~ientlfic groups ready to of it, is a A~'rt~,n-wall counter, a .,,en..,itive dehne their .,~'ience in terms of how it torm of (;eiger-Muller counter, devel- Literature: L,bbv et al., 'Natural Radio- was conducted; in this cam', from a rt~'ket Olm,d earlier by I.ibbv. When the outer carbon from Co~,mic Radiation', PlnlSiCal according to the Natv's netxts cvhnder was tlited to+slide the inner one Rei'n'w, 72 (15 Novem|x~r 1947). LIbbv et again>t one end, one half (~l.v, the ~ample ,d., 'l-he llalf-l.lfe of Rad,~:arbon (C 14)', Object: National ,Mu~,um of American hal0 ot the tuner cx hnder surrounded the I'hustcal Re;'ww 75 (15 June 1949). Libbv ! t P;torv Acce~slon No. A I ~P~4-~X)I/'~kk). .~'reen-wall cot.nter lhe count made, the et al., 'Measurement of lz~w Level Radio- apparatus wa,, hpped the other way, carbon', The RcPiew Of Scu'nhfic lnstru- bringing the other (uncoated) half around ment~, 22 (April Iq~l). Literature: D.H. De\orkin, Scn'nct" with a the .~'reen-x~all counter Ven~can,-c INew "~ork: Springer, i~42), pp. 135-140, 107-220. Atomic Clock Based upon Absorption lhus LIbbv determined the count rate of of Microwaves in Ammonia, the sampk, and then, without opening Constructed at U.S. National Bureau of S [:~,,,,~ble about the dates of the Mulh,r tubes (Fig. ~ rear) which were agency responsible for +,,,cientilic and ohlt'Cts they trod brace it is rare ft,r an conntx'tecl to the counting circuit in 'anti- technical r,tandards. ()he basic quantitx; artltact to bear an In,,cription, say, coincidence' tashion, allowing cosmic however, remained ~'vond its purview: allo+vmg =t to be dated exacth, it was a rays to be rtltx'ted. Ihe tmal mea,,ure time, for which the roiation of the earth revolutionar3.- development when in lq4q for m,nimh, mg external radiation was provided the standard and the U.S. XVdlard hbbv, an authority on the ench~mg the enhre counting apparatus Naval ()b~er'vato~. provided the author- theme, try ot radioactive ,,ubstances, in a masswe into shield (not ¢olhx'ted). flative reading of it. Although trom the ,,bowed ihat fl is posslhh' to determine inception of their work, physicists at NBS the age of organic materials bv mea~,ur- lhJs .,~-calh,d radiocarbon or carbon-14 had before them the cynosure of a mg their x ere weak radtoactiviiv. For this flaring meth~d, which [.Ibbv fle~eloD,d complete and interconnected set of achwvement he was awarded the N~ff~'l as the outcon+e of a serif.,, of re,,earchts fundamental physical quantities based I'mze for chem~t~ In lq~l begun m 1+4fi, take., advantage Ill the u~m the invariable propertit,,s of ~me gradual decay of the small amount of one or few atoms, and although they radioactive carbon-14 which ex.e U, living worked toward this goal tm several lhl,, ts the apparatus that made tht~. fronts in the hallowing decadt.'s, atomic mea,,urements (l:ig~, ~ and 7). 10 date a organ,sin t)tmtains. I+lbbv had tirst .,,hown tmn' remained inacct~sible because .so -.amph, l~t had to contain at least a certain that carbon-14 t, xist~, Ill I'iving matter, and freely subdivided. ([he linear dimensions alllount ot carbon from a once-living determined its abundance then. (it is of atoms are fully l0 : ram, while the time ,,our(e), [.Ibbv extracted its carbon. generated ill the atmosphere by cosmic rays and eventually as',imil~lted by .,.cah, of their optical t~cillations is 10" tlaborate chemical treatments ensured ~'conds.) tha! =mpurflies were mimmized, lit' pl.'mtsl 5illce an organism ~,tops taking apphtx| the carbon powder in a laver In carbon-14 at death, the proportion of il+~slth' half of a two-part brass cylinder Its carhon that is radioactive then begins Although time l~'r ,,~, was bevond NB,H's reach, one of the tasks thai NBS tt~k lFIg. ¢~ foreground, left anti right'- note to diminish; when thi~ dmlinishment is carbon in left half; ~.tween ha]ve~ is a accurately measured, the time elap.,~'d ul~m it.~qf after the First World War, to meet the requirements of the proliferat- p.x-e for iommg them), lhe other half since death can be calculated In terms of remained bare as a control. |his cylinder the 5,720-xear halLIih, of carbon-14. ing telecommunications technologies, shd into another one, half again as long was standardizing the regular subdivi- .,,ion of time - i.e., frequency - ek,ctro- (In front of plywt..J support, with cap at Ol#ect: National Museum of American n~htL which was then sealed up. nicallv (ha~.d on electro-acoustic crystal ihstorv Accession No 2.'~K~)I M~|t'rn o~'ill,+ltors), in World War II and ira-

I~ Bulh'tm of the %clentltlc Im,lrmm,nt .~wtetv No. h3 (l~) Fig.8 NHg ,H,,nu," clock, tnmt mew. Fig.t~ S~mu" ,~humc ch~'k from tin" &~,'t

mediateh.' after NBS received large hinds behind face of squatting man), his ~'ction NBS's announcement earh,' in January' to extencl its standardization capabilities was uniquely equipped to transform 194~ was caretully preparett and made a to the hundred thou~nd times higher such a frequency stabilization .~'heme big splash in the technical as well as the frequencies of microwave radar. Physicist into an o~illation counting devk~.,, i.e., i~pular prt,~s. And although this hrst Harold lxons headed the Microwave an 'atomic' ck~'k (Fig. 8). atomic clock was in no .~,n~, prachcal or Standards ~,ction cwated to this end, competitive - umr=terrupted operation overseeing the development o1: elaborate lasted only a few hours at best, and chains of electronic frequency multipliers stabdltv (I(P) was .~hghtly k.'ss than that to carry NBS's liX1 kHz standard fi'e- With his collai~wators. L-,pecially ~,nja- of the t,arth's rotatmn - it estahhshed the quenci~'.'s into the gigahertz range. min Husten (standing ilgt,w adiusting concept and the goal of atomic ch~'ks m di.,~'riminator in Fig. 9), Lyons achieved wide clrclt~ of the .~'wntlttc-techmcal this in August 1948 Etfi~rts then con- world, and beyond, as a ck,ar desRier- in the winter of 1947-48 [.vons became centrated u|xm packaging the chwk in atum to be pu~ued wdh whatever new aware of the success in .~,veral labora- two standard electronics racks bolted means became available tories in applying high fn.,quency radar together and ~t on casters; atop the techniques to the stabilization of the racks is mounted an electric ch~'k wlth (}hiect: Nahonal Mu.~,um of American frequency of an (uncallbrated) klvstron the ammonia-filled waveguide (gold |iistorv A~.-t:t.,bsitm No IqSSt)7~0 t;dt of microwave t~,.~cillator through a fet~.ihack around it. platt~,i) coiled Visible on the National ln.~titute of Standards and mechanism locking the t~ctllator fre- cath(Me ray tube ~'reen (front upper lechnology. quency to that of the exceptionally strong right) is the intensity of microwavt.'s 24 GHz abswption line in the spt~-trum transmitted through the waveguide as of the ammonia molecule. He recognized function of their frequency. ]'he deep dip, Dterctun~: P. Furman. 'lhe First Atomic that, with his chains of frequency multi- due to the ammonia 'inversion transi- Ck~'k I'rl~ram: NHS. 1~47-1~r~4', I)r(~,','d pliers working up from preci~ly calf tit)n,' is converted by the di~nminator to m,~s of liE; ~,'zvntc'c'nth Anm.d I)r,'cl~ "Tm:,' brated 100 kHz quartz crystal trscillators, an error signal controlling the frequency and Time luh'rl~d If'TEl) At,t,hc,ataon~ ,rod and chains of frequency dividers work- uf the quartz oscillators, and thus the rate Phmnm,~ Meeting, lqA5 (NASA, I~1, pp ing down from them (above head and of the 'clock.' !-17.

Bulletin of the .'~.'wntlfic Instrument .~-wty No 63 (19L~) Iq Dobsonian Telescope 11982) [X~b.~mian teit.,scopes are now ubiquitous at any gathering of amateur astnmomers, bte1,cn Turner but the revolution is far from over. Amateurs continue to experiment with As we get more serious about collecting new renovations that go far beyond the history of 20th century science, one of Dob~m's original vision of a 'Sidewalk the most daunting tasks is tt !eal with Teh.~cope'. Computerized drives, high the sheer volume of ~hat can be tech materials, electronic cameras and collected. One approach to the challenge more continue to push the limits of what of selecting what to preserve is to k,~k for amateur astronomers can do. The Dob- an, as where several stones intersect. For .~)nian Revolution is a 2tP century stot 3, me, amateur science - t.'specially amateur that seems certain to keep unfolding well astronomy - is such a place. into the next millenium. ha the last forh' '~,'ears the capabiliti~,'s of Object: National Mu~um of American amateur astr~;n~mers have increased Histom' Accession No.1994.0399. From dramatically. Tt~av an amateur can take Dr. Ronald S. Wilkin.~m. pictures fr~m their backvard that rival those once available onh' from the great Macrometer, interferometric Surveyor 200-inch telescope on Mount Palomar. (I 9~42) Part of this remarkable increa.~, in F~wer Fig.10 Dob~mi, m tcles,',~pe comes from the migration of technology i)el,~nah /. Warner fn~m professional ob.,~,rvatones - CCD large amateur tele~'ope at this time was cameras, computerization and ~phisti- As the end of the century approached, I cated ~ftware - but most amateurs typically 8 or 10 incht~ in diameter. Like the instruments u.-~l by professionals, began collecting the electronic instru- would give equal iml~)rtance to the 20'" they were almost always equatorially ments that revolutionized surveying century revolution m telescope design and g¢~desy, during and often because comm~mh" referred to as the 'Eh~b.~mian mounted, as rigid (and iaeavy) as their makers could build them and often of the Cold War. Notable among these is Revoluti(~n'. Although inspired by a real the Macrometer H Interferometric Sur- individual, the story of the Eh~:~mian permanently installed in one location. Like the professionals, tbe implied goal veyor, the first system that could deter- tele.,~'ope (Fig.lO) is as much about mine the position vector from one survey changing the way amateurs appn~ached of most of these instruments was to produce long exposure astrophoto- mark to another with centimetre level in.,,trument making as it is about a single accuracy, or better, in all three dimen- mdividual's design innovations. graphs. By contrast, Ek~,,~n's telescopes were all either 12 inches or 18 inches in sions and over very k)ng distances. The Macrometer derived from Very Long diameter - which increa,,~l their light In 1957 John Dobbin was a monk of the gathering area by up to five times. Since Baseline Interferometry (VLBI), an astro- Ramakrishna order, living in a monastery Dobson had no interest in photograph); nomical technique introduced in 1967, in San Francisco. He was k~king for a his telescopes could be (comparatively) and it led to differential GPS. wav to reconcile the thinking of ancient much lighter and were Fn~rtable and India with m~em western ~ience and The key idea was Irwin Shapiro's easv to u~. l'hev were cheap and, had become interested in ,,~eeing the aitl~ough his early instruments did not realization that if one could observe a universe first hand. He .,~,m found out have perfect optics, the amount of light celestial radio source from widely-spaced that to ~'e the deep sky obiects that he that the,.' brought in allowed them to telescopes on earth, one could use that was most interested in, he would need a give surprisingly go~ views of the radio source to determine the distance tairh' large telescope - and since he was heavens, it t(x~k nearh: ten )'ears for between the telescopes. Shapiro as- living under a vow of povert.v, this meant the Sidewalk Astron(;mers to refine sembled scientists from MIT, the Hay- that he would have to make the telescope Dob.,~m's designs and for amateurs to stack Observatory, the Smithsonian him.,~lt. His first real effort was a 12-inch Astrophysical Observatory, and NASA, reflector, for which he ground the mirror realize the advantages that they offered, but in the late 1970" a comb(nation of to develop a VLBI system suitable for from a ,,,lab of marine I~rt-hole glass. He events finally brought these telescopes ge(~esy. Although individual members made the tube from scrap cardboard and came and went, the core remained the mount from discarded lumber. This to the attention of large numbers of amateurs. together. led to other instruments and he was .,~on actlseh.' engaged in making more tele- In 1969 the team used observatitms of scopes and using them to teach astnm- quasars to determine the 845-km base- omv. He put wheels on his tek.'~COl~.,s In the early 1980", the Coulter Optical line between the Haystack Observatory and, de.,,plte the di.,,approval of his Company began offering mirrors, up to in Massachusetts and the National .,,u~,rlors, on ck'ar nights would take 17 inches diameter, specifically aimed at Radio Astronomy Observatory in West them out of the mona~,te~', pulling the~, the Dt~sonian market. During the 1980" Virginia. The uncertainty of this deter- large instruments around the area and they pnxtuced affordable, high quality mination was 2 metres or less. In 1977 ,,,howmg pas,.ers by the heavens. In 1967, mirrors in sizes up to 17 incht.,s and the), described VLBI as 'one of the most was exwIl'~t from the monastery [-~bson ~n)n became the first commercial firm to promising tools now under discussion and .,,oon founded the famous San offer complete Dobsonian telescopes. for making global scale get~etic mea- Francisco Sidewalk Astnmomers - a club l'hese instruments were extremely pop. surements', and announced plans to dt~.iicated to showing people the won- ular and Coulter struggled to keep up 'implement a system expected to be ders of astronomy hrst hand. with the demand for them. The Eh~b.~- capable of making transcontinental nian in our collection is an earh' 13-inch length measurements with 5-cm accura- 1he instruments that l.X)b.,~m developt~l Coulter 'l-X~b'. It was purcha.,~:l new in cies'. While this quasar research was during this peri~i ran counter to every- 1982, after a waiting period of over six pn)gressing, another team concluded thing that amateurs had been doing. A months. that interfen~metric tracking of a corn-

20 Bulletin of the %'ientitic Instrument S(~'ietv No 63 (1999) munications satellite could yield useful Object: National Museum of American gel~etic information, and that VLBI History Accession No. 199%0013. From ob.,~,rvations of artificial satellites could Western Atlas International. be made by small, portable antennas. Biolistic Particle Delivery System Chark.'s Coun.,~,lman, III, ai~ of M1T, CornelllStanford 'Gene Gun', devised a VLBI technique flw tracking Prototype ill (c. 1985) Apollo astronauts on the mlnm. I'his inwdved differencing the phases of radio Patricla Ca,s~q waves arriving simultaneously at a point from difterent spacecraft, and taking the The rapid development of apparatus flw difterence of these differences between cellular genetics and molecular biology two different receiving points. This since the lq70s has created challenges hw 'double-differencing' technique was u.,,ed curators building historical instrument in the Macrometer, and was the key to its collections. Clearly, it is easier to collect geodetic accuracy. the apparatus when it is readily avail- able, but will the apparatus in wide use In 1978, Coun~lman and Shapiro pro- today be of lasting historical importance? posed MITES (Miniature lnterfen~metry To build the genetics and molecular Terminals hw Earth Surveying), using biology collection, I visit trade fairs that portable antennas and phase double- accompany .scientific meetings, tour la- differencing of signals from GI~3 satel- boratories, and follow the current Iitera- lites. This work was supfx~rted by the Air lure. i focus on instruments u~,~'d to Fig.li Bmlistlc t,artMe dchverll su, h'm Force Gt~physics Laboratom, which saw separate, purify, and analyze biological pr,,tatype ill or 'b~ene gun'. it as a way to measure the small natural molecules in the techniques of centrifuga- and man-made motion effects around tion, chromatography, electrophoresis, missile silos. In December 1980, MITES and spectroscop~; as well as electronic cells of an onion. Remarkably, the cells antennas were .seton survey marks about cell .,~wting. I al~ collect th(~e instru- took up the particles without being IiX) metres apart, and achieved results ments used to intn~uce genes into a new killed Two more prototypes that used that were accurate to within I centimetre host, a process called genetic transforma- gunpowder charges to drive particles in all three dimensions. tion. into cells successfully introduced genes into a variety of plants. Counselman and I~mald Steinbrecher - A second strategy hw building a con- an MIT electrical engineer wh(~e firm temporary collection, is to collect the While the Sanflwd and Wolf 'gene gun' had built the MITES equipment - then prototypes as well as the commercial was in the patent process, Dennis E. fiwmed Macrometrics, Inc., to commer- instruments, in the belief that the proto- McCabe, a scientist at Agracetus, Inc., an cialize the new technology. Counsel- type provides a sen~ of the innovation a agricultural biotechnolog.v firm in Wis- man's main challenge was figuring out scientist seeks in order to accomplish a consin, heard about the idea. tie devi.,~'cl how to determine position from GPS particular research goal. The advantage a version that uses high-voltage electri- signals that required no code knowl- to collecting this material now, rather city to vaporize a drop of water, creating edge, no steerable antenna, and only a than waiting a decade or more, is that the a shock wave to drive gene-coated small part of a VLB! signal-processing instruments can be acquired in excellent particles into the cell. [~th the Santord system. His patents (the first was condition with the owner's manuals and and Wolf and the McCabe 'gene guns' granted on March l, 1982) were even- patent records, and the inventors and were eventually produced commercialh'. tually licensed to Ashtech, Trimble, and instrument makers can be interviewed Prototypes of both versions are in the Litton Industries, and employed in most fiw the historical record Such a complete collection at the National Museum of dual-band GPS receivers available to documentation of an instrument pro- American History (Fig. ll). civilians. vides a valuable historical record of the process of invention, whether the appar- In I~-N, Sanh~rd collaborated with Ste- Publicity fiw the Macrometer began in atus proves to be of lasting scientific phen A. Johnston at Duke Universi~' to early 1982. The Federal Ge~vdetic Control value or not. devi~ a high-pressure helium gas sl~ock Committee tested the system in January, to replace the gunl~wder mechanism in 1983. The National Geodetic Survey The biolistic system of gene transfl~rma- his ~vstem. Within ten years, DNA acquired two units in March. Further tion, or the 'gene gun', is an example of a particie guns have become one of the tests conducted by the German Geocletic recent group of prototypes in our collec- .,,tandard laborato~' options for gene Survey, the Canadian Gts~etic Survey, tion that has proven surpnsingly valu- transfer Today, hand held versions that and the Finnish I~ard of Surveyors, able and interesting. John C. Sanford, a are fired with miniature gas cartridgt.,s provided results better than I :~X),t~X} or Cornell University plant geneticist, are being u.,~d to transform am,' kind of three times better than first-order stan- sought a way to cieliver foreign DNA cell, tissue or organ, under both m ~'ltrt~ dards. into plant I:ndlen as a way to transform and m ~,iz~, conditions. New uses of the agricultural crops. After failed attempts gene gun for delivery of DNA vaccines Aero Service bought Macrometrics in with the meth(~s available, in 1q83, he and other drug therapies are undergoing 1984, upgraded the private tracking met with Edward D. Wolf, an engineer clinical trials in 1'-,~-~. This laboratory network that Macrometrics had estab- and director of the National Nanofabrica- research instrument is already finding its lished to determine GPS satellite orbits. tion Facility at Cornell. They came up was" into general medical practice. The Macrometer I1 was intr(~uced in with the idea of using small particles, April 1985, and later advertised as 'the coated with genetic material, to actively Objects: National Mu~um of American only c(Meless, dual-frequency GPS re- carry the new gene into the cell. The first History, Cornell/Stanford Gene Gun, ceiver available tlxtay'. By the late 1980", prototype was an air pistol they used to prototype il, Accession No. lqql. the Macrometer was ob.,~lete. shoot small tungsten particles" into the 0785.02; Cornell/Stanford Gene Gun,

Bulletin of the .~k'il~tific hxstrun~nt ~cietv No. 63 (l~) 21 prototype Ill, Accession No. 19~1 t17t'i'301 (pwtured): Agracetus/McCabe t,ene Gun prototype. Accession No. I '~3.03r"qO !.

Literature: lohn C..'~mford, 'The Biolistic Process', Tremt, m Bwtcchmqoy, y, 6 (lkx'ember, 1~8~l, pp. 2'~-302 (on the .qanford Bioh~,tic apparatus), i'aul Chris- tot,, lh, nnis E. McCabe and William F. .qwain. '.':;,table lran~,formation of ~wbean Callus by l)NA-Coated (;old Pariicles', l'hmt Pl{u,u,h,,~:V, 87 (I,SS), pp. 671-074: and Ning-Sun ~ang and I'aul Christou, ~wls, I'artwh' l'h,ml,ardment Teclmolocy fi)r G¢'~tt' gr,msfi'r [(.Nford: Oxford University Pr~s, i b'q4).

Prototype Thermal Cycler for PCR, 'Mr. Cycle' (1985)

Rdm!tlhl~ KOIhfrdhl~

IYCR (i'olvmera~. Chain Reaction) is a I~w~ertul and versatde meth,~t ot identi- f.vmg and rapidly repr~w3ucmg fragments ot DNA. I'CR machlm.'~ are as ubiquitous today in biomedical laboratories as phot0copymg machines are in business Fig.12 'Mr Cy('h". offices.. They can make millions of copies of any pi~x'~'of DNA in lust a few hours. target .,~'quence are prcMuced. Every withdraw aliquots of enzyme ~flution ]heyare [x'ing u~'d in a great variety of cycle doubles the amount of the target from the tubes in the back block, and ways - including to detect pathogens, to .,,equence (thus the term 'chain reaction'). deliver them into the corresponding clone gent's, to identil~' criminals from After twenty cycles there are more than samples in the front block. This proce- I)NA tragmcnt,,, and to studv evolution one million copit.,s of the DNA fragment. dvre had to be repeated eyeD, cycle by analy,,mg the DNA of l(~ng extinct because the Klenow fragment was c rea tt, res. Since Cetus was not primarily an thermally unstable and fresh enzyme instrument company, they formed a joint had to be added after each denaturation lhe idea fiw I'CR was conceived by venture with the ~ell-established instru- step. This made the process tedious and Karv B Mt, lli~ in lug3 and develoF~.t ment company, Perkin-Elmer Corpora- resulted in the rapid accumulation of by h,n and his colleagues at Cetus tion of Norwalk, Connecticut to make denatured enzyme in the ~mple. Later Corporation, a biottx'hnology company an instrument based on the PCR prototypes and the first commercial m Emervville. California. ]heir pal~.,r technique. 'Mr. Cycle', pictured here instrument u.,~d a thermostable poly- de.~rib,ng the earliest application of (Fig. 12), was the first instrument built mera~ (Taq DNA Polymera~) as well I'LR. and the first paper to appear on and tt~tt~l in 1984-1985 by this joint as electrical heaters and refrigeration IX'R, ~va~ pubh~,hed m Scwm'; in 1985 venture. It consisted of a multi-channel units rather than water baths. Perkin- For hl~ work. Mulhs won the Nobel automated liquid handler, called the Elmer Cetus introduced the first com- I'n/e in I~.O,. Pro/PetteIM, h¢,~kecl up to two water mercial instrument, DNA Thermal Cy- baths (not pictured here). The Ix~l of the cler I (TC-I), in 1987. lhe pr¢~~,s L', qtute ~qmple. In a tl,~t tube, instrument contained two temperatuw the ~'lente, t,, combine a double .,,trand of controlled aluminum bh~'ks. The front Object: National Mu,~um of American DNA containing the gene or fragment to block held the sampIt~ (in uncapped History Accession No.1993.0166.01. D~ by copLed (the target .,~'quence) with micr¢~'entrifuge tubes) and was con- hated "by Roche Molecular Systems, Inc. chemical raw materials u.,~xt to build nected by a ,~witching valve to two 'Mr. Cycle' is currently on display in the new L)NA ~trand.~ (precursors); two water baihs, one at 94 degrees Celsius Science m American Lift' exhibition at the •,hort. ~,,ngle strand,, of I)NA (primers) and the other at 37 degrees Celsius. The Smith.,~mian Institution's National Mu- e',p~wlally con.,,tructed .,~) that they will lie back block held ,,~dutions of Klenow ,,~'um of American History. on either ,qde of and bracket the fragment, the DNA polymera~, derived fragment to be copitM: and the DNA from E. Coli, aim m uncapl~M micro- Authors: DavM Allison; Paul Forman; pol~ mera~,, the en,,vme catalyst for the centrifuge tubes and placed in the same Patruia Gosse/: Ramunas Kondratas; Roger reaction ]he mixture is heatlld, causing configuration as the sampIt~ in the front E.Sherman: Stev,'n Turner; and Deborah ]. the I)XA double >trands to ~'parate, and block. A controller kept track of the Warm'r all at the National Museum of then c~led ,,~ that each primer can bind incubation timt.~ at both high and low American ttist,,ru, Smith~mhm instituth,n, to it, comphmentary ~'quence on a temperatures, actuated the switching Wa~hmxhm, L~ 21k%0-0036, USA David ~trand I'ohmera~, ~,tart at each primer valve in order to change the front bh~'k DeVorkm is at the National Air and Space and copy the ,~'quence of that .~trand. temperature, and prompted the multi- Mus,'um. All dlustrathms C,,urtesy Smith- ~,~lthin a ~,hort time. exact replicas of the channel head to pick up frt,'sh tips, ~,nmn Institulion,

"2 Bolh.t,n o! the ~',enhtu" In~trunwnt .'~.u.ty No 03 (lq~'~) Ten Important Twentieth-century Items from the History of Science Collections of the National Museums of Scotland A.D. Morrison-Low, R.H. Nuttall and A.D.C. Simpson

Fhe collections of the National Museums of ~'otland embrace most of the natural and man-made worlds, and the most recent exhibition there - the Mu~um of Scotland - which was opened (m ~) November 1998, includes a gallery devoted to the twentieth coatury. Spon- sort~ by ScottishPower, it displays three hundred aems ch,~en bv the people of Scotland fl,r their significance to Scotland in the twentieth century. In it may be fl,und how science has permeated twen- tieth-century everyday lives, through telecommunications, medicine, transport and power in the home.' The social history of science is, however, led by prototypes in industry and the labora- tory, before it is domesticated; other items remain in specific fields of applica- tion and are only known to specialist workers. The ten items selected here - roughly one for each of the decades of the century - are not to be found on the Museum of Scotland's Twentieth Century gallery, but will, in due course, form part of a prol~xt Twentieth Century Science gallery, in the adjacent Royal Museum.

Of court, pt~)ple don't wake up and think: 'Hey, it's the twoatieth century!' and create new designs for instruments: thus the earliest pieces evolved out of the brass and glags we know and love so well. New materials reflected develop- ments in materials technology. For in- Fig.1 four-m,'h alummium ~xtant bu Cary, /amd0n, c.1900. stance, the small 4-inch aluminium Trustees of the Nat,onal Mu~um t~ Scot/and. sextant included here (Fig. 1) L~ one of two in the collection of the type designed of British scientists working at the British A~,~ciation for the Advancement and made by Cary of London for Imperial Universi~' in Tokyo: J. Alfred of Science at the time when this mstru- navigation on the British Antarctic Ex- Ewing (1855-1935), the Scot who held the ment was acquired for the Royal Ob- pedition of 1t~)1-1904, and carried by Chair of Mechanical Engineering and servatory, Edinburgh, as part of the Captain Robert Falcon Scott's team Physics, and his colleagues John Miine British Association's seismology network across the land mags in an early un- (18~-1913), Profes~r of Geology and (Fig. 2). It L,~ numbered 32, and can be successful attempt to reach the South Mining, and Thomas Gray (1850-1th18). dated to 1~). * Milne acted as an advi~r Pole.: Portability was increased by its They pioneered the modern science of to the London instrument maker R.W. compact size; being made of an alumi- seismol(gy. Ewing established the Seis- Munro (1839-1912). who develolr~M and nium alloy, it was I~,th lightweight and mological Observatnrv at Tokyo and manufactured the Mflne ~ismograph, strong.' in addition, the low thermal returned to Britain in 1883 after five and it played a significant part in capacity of the metal meant that the years in Japan. He was a notable establishing Munro's reputation. An im- user's fingers did not freeze to it. promoter of technical education and, as proved version called the Milm-Shaw However, its shape is clearly derived Sir Alfred Ewing, was Principal of the seismograph, incorl~)rated high magnifi- from a much older and traditumal University of Edinburgh ~m 1916 to cation and magnetic damping, was pattern. Aluminium was also used in 1929. Ewing's 3-comD~nent instrument intr(~uced in about 19147 other instruments, wherever its charac- of 1882, marketed by the Cambridge teristics proved useful. Scientific Company, was the first to rt,~,lve all three movement coml~moats A colleague has remarked that collecting Mechanical devices of unprecedented and record them separately. material trom the twentieth century is sophistication were being produced, 'constrained by a number of factor.,, often taking advantages of these new including the" sheer proliferation of materials. By the end of the nineteenth Yet another connecti(m with this Edin- material, the increasing rate of renova- century sensitive ~ismographs were burgh group was Milne's 1895 develop- tion and greater sublect speciali~tion. developed which could record the com- moat of the first horizontal-pendulum The first factor means that collecting l~ment forces and duration of earth- ~ismograph capable of detecting the must be selective, the second that quakes. A number of these instruments much lower frequency vibration of very considen.~d apprai~l of significance is were developed in Japan, where ~vere distant earthquakes. Milne was Secretary, difficult, and the third that external earthquakes are experienced, by a group of the Seismology Committee of the ex[~.,rtise must often be sought. '~ in

Bulletin of the .~ienfific Instrument .'~x'ieW No. 6,,I (l~) 23 galvanometer ~ale, Lundegardh burner and sprayer ves.,~q and photographic plates: the entire apparatus was offered as a package by Adam Hilger Ltd., in their Catalogue of Spectrographic Outfits fi~r Metallurgical and General Chemical Analytical Analy.,ues, 7th edition, 1936/ Mitchell, who died in 1982, continued his work in this field, and his 19.18 ~n~k The Spectrographic Analysis of Soil~, Plants and Related Materials is regarded as a classic work in the areas which it covers, in particular, this exercise of collecting modern apparatus demonstrated that ,,~me significant examples of the Hilger ..00....0 0.0. I 'Spekker', an im[n~rtant standard instru- ment widely u.,~,cl in metallurgical ana- lysis, in Scotland, as elsewhere, were unrepre~nt¢KI in museum collections, and that the opportunity for collecting certain important types had already pas.,~:t.'" I i The u~ of aerial survey photographs in No. l:'/.t3. ~: full ~ize. mapping, although just one aspect of photogrammetry, is a matter of priority Fig.2 Mdnc's Horizontal Pendulum Se~smogr,zph, ,!~'red fi,r £75 in the Gm~bratk.e Scient{fic in wartime and of economic and ,,a~cial Instrument Co. Ltd.'s l.zst No. 42 tot 1.~6. Trustees Of the Natamal Museums of Scothmd. imFn~rtance at all times. In the years between the two world wars aerial mapping of unsurveyed territory and the revision of existing ground surx'ey data was increasingly practi.,~-KI. Though a large number of map-plotting devices were developed in this peri(gl, including in Scotland Ban" & Stroud's 'Big Bertha'," it is usualh,' considered that two compa- nies, namely Wild in Heebrugg and Zeiss Jena, made major contributions: the two best-known instruments of this peri(gl being the Wild A5 Autograph and the Zeiss C5 Stereoplanigraph (Fig. 4). in- deed, it is notable that both continued in pngiuction into the fn~stwar era albeit incori~rating various improvements.

A large and complex drawing instru- ment, the Stereoplanigraph principally enabled the plotting of planigraphic and relief features from stereo pairs of aerial photographs. The Model C5 in the Mu.,~,um's collection could also be u.,~-~d with a ten.t~trial stere~camera for exam- ple to create a high precision plan of a building, or a pair of phototh~olites to map mountain terrain.': The instrument has two main components: a ~phisti- cated stereo viewer which creates a Fq43 t,,~:t,'.l/,,.,n=/ /da,t.\'ra/,h ~,t l.un,h',\',mth ,~/,t~m,ltu.. u.cd m pamccru~y, t/a' subjective three-dimensional image in- .t,,'~ tr¢ ..... ya ,malu,r, ot ~od; at the Ma,ndatl Institute ~r Soil Research, Ah'nh'en, c.1936. corporating a moving i:n~int which can [/a' ,~,la~,mla=/In~t~tuh'. be positioned anywhere within the image volume; and a mechanically-connected lush, the National .Mum'urn,, appointed a An important example was the apparatus mapping table. Negatives or diapositives Re,~'arch Fellow to a,,.,,i~,t them m the u~,d by Dr R.L. Mitchell of the Macaulay are mounted in two projecto~ (fitted ','lect,*n - bia-.ed towards, obiect.,, in the instituie for ~,il Rt.-,earch, Aberdts,,n, for with similar ien,,u,~ to th,~e u,',~] in the ph},,,cal ,,.lence,, with a Notti,,h prove- .,,oil analysis, in the first agricultural camera ,so as to correct for any optical nance - and, a.,, Allen Simp~,on has application of l,undegardh's flame Sl~.~c- distortion) which can be positioned at the recounted eb,ewhere, Bob Nuttall's ap- trum meth~gl of quantitative spectro- ~me angles the cameras occupied rela- pointment led to the acqui~,ition of a graphic analysis in the United Kingdom tive to the ground - h~r example, to g~i repre~.~'ntatlve collection of ~,pectro- in 1936 (Fig.3)." This consists of a Hilger compensate h~r oblique photographs. photoml'ter, E315 .~pectrograph, a Kipp photometer, The operator, looking through eyepieces,

24 Bulh,tin of the Scmnttfic In.,,trument ~c|ety No. 63 (iq~9) w ! These include special techniques for specimen preparation, supporting pre- pared specimens which can be substan- tial in size, the need to studv surfaces by reflection which may have only a low inherent reflectivity, and an optical system which forms a high rt~dution image of a flat surface. To overcome these (¢ostacles manufacturers have developed highly specialized instruments; bvt be- cau~ they are expensive m the first place, and as many have been u.~,d in a factory environment the number sun'iv- ing is lower than that of transmitted-light instruments; in addition since the,,'often lack the aesthetic qualities, and indeed the portability which attracts man,,' collectors of micr(~copes tbey are un- der-represented in man,,' collections.

In the peri~ 19~)-60 Leitz in Wetzlar made a substantial research investment in the development of incident-light and metallurgical micn~copes and their op- tics, resulting in the emergence of the Orthoplan and Metalloplan conventional Fig.4 Zeiss C5 Stereophm(~,raph m Ol~cratmn, c.1941J, ttvm B.B 7allcll. Engineering models, and the MM5 and the MM6 Le Applications of Aerial and Terrestrial Photogrammetry fNew Yark, 1938). Trustees of the Chatelier-type reverted microscopes. National Mum'urns t![:Scotland.

hdlows the x and y co-ordinates of The twentieth century has been remark- objects in the image with two hand- able not just for its investigation of the wheels, and z (heights) with a foot building blocks of life at micr(rscopic and '% control. These scaled points are trans- smaller level, but reaching upwards and ferred by rods to the drawing table where outwards to examine the environment they are plotted to create maps over a which gives all Earth-bound life warmth, range of scales)' including astronomical investigations of the Sun from space, becau~ so much of its spectrum is absorbed by the Earth's A classic area of science undertaken just atmosphere. The Museum has the proto- after the Second World War was the type for an instrument, developed by investigation of the complex structure of University College, London, which was DNA. Its chemistry was understo(xt by launched in August 1969 on the Amer- this time, but this did not allow an ican satellite O.S.O.-6, the sixth in a series understanding of its mechanism of self- of NASA 'Orbiting Solar Obsen'atories', replication. Pioneering X-ray crystallo- which were designed to study the graphic work by Rosalind Franklin components of the Sun's radiation (1920-1958) and Maurice Wilkins (Fig.6). This particular instrument exam- (b.1916) at L)ndon University provided ined the Sun's radiation in the ultra- vital clues, but the solution was finalh/ violet region. ~" It is a grazing incidence revealed in 1953 by Francis Crick (b.1916) grating ]~dvchromator for ob.,~,n'tng the X and J.D. Watson (b.1928) of the Cavend- whole Sun and measuring solar flux (and ish laboratory, Cambridge, who demon- upper atmosphere absorption cn~ss-sec- strated that DNA is comp(~,d of two tions) in eight extreme ultra-violet emis- identical chains twisted together in a sion lines between 180~ and llt~)A, with double helix and linked by paired base a cylindrical concave grating in a Row- groups." This model (Fig. 5), made of land circle mounting with eight channel cardboard and copper wire, was con- electron multipliers. The truncated sec- structed by Crick him.~lf, for a visit to tor-shaped ench~-'d structure was fabri- lecture at the University of Edinburgh in cated in a dark-painted alloy with an 1953, and although it iacks the detail of entry I:n.~rt window on the outward face, later miMels, it would have helped his with electrical assemblies mounted audience to unde~tand its complexities. above; the entire experiment was inserted In 1985, Crick recalled that 'as far as l in one of the nine bays in the rotating [ I know this is the only one I made. I doubt spacecraft platform. '~ if it has ever been iliustrated anywhere ... it was m(rstlv likely in the late spring or Metailographic micn~scopy pt~;es a num- Fig.5 Mt~h'l of DNA ntoh't'uh', constructed earh,' summer of 1953 and I must have ber of problems not present in conven- I~/ Fr, mcis Crick m 1953. Trush'es c)[ the made it before ! came to Edinburgh"' tional transmitted light microscopy. Nahanal Mu.~'ums t?f Scothmd.

Bulletin of the .~lenhfic Instrument ~x-ietv No. 6.~ (1~) 25 l'hese were made available with newly- developed optics, which by 19b0 in- ~ ' U~ivlllliy Cilliill L~ cluded the first flat-field apochromatic fL, -. lo~er UV hl~ckmamt0¢ Prlac;lml Inv~ntlgotor: It. k. F. ~1 obwctives to be designed for use with "\ i (~tiicllvtll St~ r thiHtl I ~), He II (~), opaque specimens. These could be com- bined with wide-field eyepieces allowing examination of much greater areas of the specimen at a single level of focus than did earlier optical systems.

The construction of the MM6 (Fig.7) features an inverted viewing arrange- merit with the stage placed above the Oblective thus allowing for examinati~m I/ +.,.in'- . #\ v - li • ii of large coml~w~ents, as in the failure Untve~ e/letoene analysis and quality agsessment of aero- 20-200 Key X-my T4Le$cope components which was the original frle

The invention of imaging devices which can create pictures of the .~lft tissues inside our bt~ies is the most significant development in medical diagnosis in the last thirty years. X-ray photographs, which represented such a startling ad- iili vance in 1895, show the skeleton well, ...... but beyond that they are severely limited. Several new techniques can now reveal in ~7~N6 8 ?~ 131 128 121 detail the internal organs and the tissues which connect them - and ai~ abnorm- alities such as tumours. Fig.7 Diax,ram showing the fi'atun,s of the MM6 u'idefield metallognlphic microscope, Magnetic Re~nance Imaging (MRI) is c.197o, from Er,st Leit: C,MBH D-6330 Wetzlar, MM 6 Widefield Metallographie one of the most important of these Micr~,cope: lnstructi,ms, p.4. Trllst,,,,s of the Nati,,nal M,.q'ums of Scotland. to:hniques. It was devi.,,,d in Britain in the 1970" and depends on a phenomen- MR! using the machine developed in on called Nuclear Magnetic Rt~lnance laboratory rat was in sufficient detail to Aberdeen. The later commercial exploi- show a clear pathology. The press (NMR) which was developed for anah,,- tation of the rapidly-evolving market tical chemistn,' after the ~cond WorJd photograph (Fig. 8) shows Professor has been led by American and Japanese Mallard examining the 'Mousebox' War. Profi.'~lr John Mallard and his companies, who have built most of the team in Aberdeen carried out some of when it was first displayed in 1997. MRI ~anners currently in u~ all over This is perhaps the most significant the crucial work, and there were tither the world The first computer-consti- teams active in Nottingham and Lon- early MRI 'relic'. ~ The Museum also tuted MRI image was pn~uced as early has an example of the first prlgluctiim don. ,Mallard was the first worker to as 1974 by Mallard's team using a small demonstrate the clinical effectiveness of version of a clinical MR! Scanner, which prototype machine: this image of a was made by Mallard's development

Bulletin of t~, .~'it,ntific Instrument ~ No. ~ (l~) Fig.8 Pro~'s~r John Malhlnf exatnim,s the 'Mousel,ox', 195U. Scotsman Publications Ltd.

company, M. & D. Technology of Aberdeen, which was installed in the Royal Infirmary, Edinburgh in iq83.-"

in the 1930", electrons, protons and neutnms were, thought to be the ultimate building blocks of all matter. Since then, a large number of different types of particles, many of them very short-lived and with apparently exotic characterisa- tion, have been pr(~uced in high energy Fig.9 L)ctcctw, cltamt,,'r m,.tdc the Bttta,h Natrmal H,l,t,h' collisions in accelerator laboratorit.,s. One Clulm&'rs, durin,¢ its tim,, as ,1 beam-line detect,,r m the Ruth,'r.tont of the greatest challenges of modem La&~rato~, Februa~. 1#71. CCLRC. physics has been to classi6,' and under- stand the relationships of these families of particles, and to detect missing seums of Scotland in 1975, where it were fed to Grangemouth. An upgrad- particles predicted by theoretical models. joined one of the earliest examples of its ing of the system provided the oppor- Some of the largest and most costly predecessor, the cloud chamber, for tunity to preserve parts of this machines ever developed have been which the Scots meteorologist C.T.R pioneering pn~ct.,ss control equipment. employed in this pursuit and located at Wil~n (1869-lqSq) won the Nobel Prize BP Petroleum D~'velopment Ltd has in 1927.-" national and international facilities. ]'he pre.~,nted one of the original off-short- bubble chamber is a type of particle telemetn: stations and significant .,,ec- detector which is particularly suitable An important suite of computing equip- tions of the twin Argus computer and for tracking the charged particles pro- ment concerned with the early develop- telemetn' interface. -'' l-here art, particular duced in high-energy accelerator colli- ment of the uff-shore oil industq, was problems with wprt~,nting the engi- sions. It depends on the fact that a liquid pre~nted in 198~1 by BP I'etroleum neering achievement of maior enter- held under pressure at a temperature Development Limited. British Petro- pri~,s such as the development of the near its boiling lm~int fails to boil if the leum's Forties" Oil Field was the first to off-shore oil industn" in conventional pressure is suddenly reduced, it remains be developed in the North Sea, and it m u.'~'um collections. m an unstable superbeated state unlt.'ss it produced oil which was piped to the is di.,,turbed. Sub-atomic charged parti- company's Grangemouth refinery. In Indeed, this material typifies problems cles shooting through such a liquid order to monitor conditions across the faced by curators revolved with collect- disturb the molecuk,,s they pass and leave recovery and distribution operation, and in K an~| prt.,servmg twentieth centu~" a trail of boiling liquid behind them; this to provide automatic control of pr,~iuc- material. Items have mcrea~'d dramati- can be photographed. The bubble cham- tion and flow ratt.,s, BP developed a cally in size, as ,,,een by contra~,tmg our ber was invented by Donald Gla.~,r at the ~phisticated computer-controlled tele- examples the four-inch radius ~,xtant University of Michigan in 1952, and was metry system, ba.~'d on a Ferranti twin and the 20-ton Bubble Chamber Not responsible for most of the discoverit.,s in Argus ~10 computer. This was linked to only does the curator (and their advi- nuclear physics during the next twenty- off-shore sitt,,s by tropospheric ~'attering ~rs) have to deal with the range and five years. The British National Bubble telemetry. It enabled engineers in the extent of m~ern apparatus, but them, Chamber (Fig.9) was built at the Ruther- operation,~ r(x~m at Dyce to monitor art, ~rious problems with stability of ford High Energy Laboratory at Harwell .,~fetv levels and to control pr,~uction coml~site materials which have to be in 1%3, h~r u~ with the Nimrod proton rates from the Forties Field and the preserved fi~r future generations in an accelerator, and at l.~)cm it was one of various other fields run by different appropriate environment At the time of the largest in the world.-': After it had operators that were later linked to the acquisition there is often no adequate been used at the CERN laboratory out- pipeline, to ensure that the correct published historical perspective, and side Geneva, it came to Nationa'l Mu- fractions to match market requirements persuading mu.,~,um directo~ of the

Bulk,tin of the .~'ientific in~trument ~cietv No h3 (ILi~,~) 27 validity o4 the stated case for acquisition 7. A.D.C. Simpson, '~ as Evidence: 20. See J. Mallard et ai., 'In z,itw n.m.r. can place great demands on the curator. The Role of Museum Collections', Journal of Imaging in Medicine: the Aberdeen Ap An important consideration in develop- Medical En,qineerin{~& Technolo~.,17 (1993),pp. pn~ich, both Physical and Biological', Philo- ing a case for acquisition will always be 172-175. st~aical TransactionsB289 (1980), pp. 519-533; the availability of adequate supporting Mallard et al., "Medical Imaging by Nuclear documentation, including technical lit- 8. R.L.Mitchell, "Spectn~graphic Analysis of Magnetic Resonance - A Review of the erature. Let us hope that the twenty-first Soils by the Lundegardh Methud', S~'ietv of Aberdeen Physical and Biological Pro- gramme', invited review paper, internati~mal century will be kinder to the curator! Chemical Industry, $$ (19~), pp. 2.67T-2~. Discu~ed in Herbert A. Laitinen and Galen W. Sym~sium on Medical Radionuclide inmgm~ Ewing (eds.), A History of Analytical Chemist~ (September 1980); Francis W. Smith, q'wo (York, Pa., 1977), pp. 1Z~!27, i32. Years' Clinical Experience with NMR Ima- Notes and Referen~ ging', Applied Radioh~,y IMay/June 1983), 9. NMS.T.19885: presented by the Macaulay Mallard, 'The Wellcome Fnundation Lecture, 1. Hazel Williamson (ed.), Nat~ml Museums Institute of Soil Research, Craigiebuckler, 1984: Nuclear Magnetic Resonance Imaging af Scotland Annual R~ April 1998-March Aberdeen. in Medicine: Medical and Biological Applica- 1999 (Edinburgh, 1999), pp. IO-!1. and Problems', Pn~-eedin~s of the R .oyal Society. of Lond(m B226 (1986), pp. 391-419; I0. R.H Nuttall, 'Fifty Years of the Hilger Mallard, 'Hevesy Mem~'ial Medical Lecture, presented 2. NMS.T.1911.34: by The Admir- Spekker', Bulh'tin of the Scwntific Instrument 1985: Some call it laziness: I call it deep alty, Londlm. Other dems in the Museum's fa~cwty.,No. 15 (19fl71,pp. 7-9. collections, taken on this expediti~m am: a thought (with apoh~ies to Garfield)', Nuclear Medicine Cmnmumcatams, $ (19871, pp. 691- sextant by Hughes (NMST.Iqll.31); three 11. B.B. Talley, Engineerin~ Applicatmns of 710. further sextants by Cary (NMST.1911.32, 33 Aerial and Terrestrial Photaxrammet~ (New and 35); an artificial I~riz~m by Watkins & Hill York, 1938), pp. 5.30-535; Barr & Stroud (NMS.T.1911.43); an artificial ~mzon by Cary Phoh~rammctrw Plotter. Report of the Air Sun~'y 21. NMS.T.1991.4: purchased. (NMS T.1911.44); a deepsea thernmmeter in a Cmnmatta, No 2 (19351, 22-125. reversing frame by Negretti & Zambra (NMS.T.1911.56); two solar thermometers by J.J. Hicks (NMST.1911.64 and 65), two mini- 12. ]'alley,0p. Ot. (note II),pp. 48~-494. 22. NMS.T.1975.27: presented by the Ruther- mum thermometers bv Negretti & Zambra ford High Energy Laboratory, Didco4, Oxford; (NMST.1911.66 and 67); three mercury, ther- 13. NMS.T.1986.376: presented by The De- other items from the same ~mrce are~. a section mometers by Negretti & Zambra (NMST. partment of Geography, The University, of the Nimrud proton accelerator (NMS.T. 1911.71, 72 and 73): a therm~mx~r by Casella Glasgow. 1981.891 and the spark chamber from the (NMST.1911.74; a hypsometer by Casella Nimrod (NMS.T.1983226). Other high energy physics material in the Museum's collection (NMS.T.I911.75) and two pairs of snow 14. J.D. Watson and FHC. Crick, 'Molecular goggles (NMS.T.1911.76 and 77). include: a Cockmft Walton electron accelera- Structure of Nucleic Acids: a Structure for tor, presented by the L~,partrnent of Physics, Deoxyribose Nucleic Acid', Nature (25 April University of Edinburgh (NMS.T. 197525); 1953), pp. 737-8; utem., "Genetic Implications of 3. For aluminium instruments, see John section of an electnm synchn~'on, presented the Structure of Deoxyribonucleic Acid', Bumert, 'The Use of New Materials m the by the Department of Natural Phik~hy, The Manutacture of Soentific Instruments c.1880. Nature (34) May 1953), pp. 964-967. See also Wats~m, Tfw Double Helir (London, 1968); University, Glasgow (NMS.T. 1975.24l;and an c I920', in J~hhn T. Sh~k and Mary Virginia J.D. early electron linac made by the Mullard Orna (eds.), The History and Pre.~n~ata,n of R Olby, The Path to the Double HHix (London, 1974). Research Laboratories for the UKAE at Clu'mwal instrzmu'ntatum (l~rdrecht, Boston, Harwell shortly after the Second World War, Lancaster, Tokw~, l~), pp.217-238; and Anita presented by the Department of Radio Ther- McCoruwll. ',~luminium and its Alloys for 15. NMS.T.1985.LI: presented by Francis apeutics, University of Cambridge (NMS.T. Scit'ntitic Instruments, 1855-1900', Annals of Crick to the University of Edinburgh. Letter 1978.181. Scwnce, 46 (1989), pp. 611-620. For the hL~kn'V hx~m Francis Crick to A. Morrison-Low, 18 of the 'D~.~overy', see Anne Savours, T/ie April 1985. Other DNA models are: VoUa.¢.es of. the "D~sc~n,ery"(L~mdon, 1991). NMST.197870, which illustratesthe 'B' form 23. NMS NPM 3287: presented by the ~ the molecule, using over 1300 components University of Edinburgh. Devised by Wils(m 4. NMST.195g.Z~I: presented by the Royal repnsented a complete turn of the double in 1910, this example was acquinrd by the Observahn'v Edinburgh. Other seismtgraphs helix, made by Sheila Gould and C.A. University in December 1913. m the collt,ction are: a Mdne-Shaw seismo- ~'¢qi'S. graph No. 3 (NMS T.1963.3): a Ewing seismo- graph, c.18qq, trom the Coats Obsen'atory, 16. NMS.T.1972.Z~3: presented by the Mul- 24. NMST.1999.82; presented in 1988 by BP Pat-lev (NMST.196639) and a J.J. Shaw lard Space Science Lal:n,ratory, University Petroleum Development Ltd., Aberdeen. hon,,0ntal pendulum ~'pe seismograph, from College Lzmdon, Department of Physics and ~qfridges. London (NMS T 198 ~i.1311. Astronomy, Holmbury St. Mary, Dorking, Surrey. 5 For ~,~.~mographs, including the Milne Authors" address: horizontal-pendulum instrument No 24, see 17. D.E. Knight, R Uribe and B.E. Wot~gate, The History of Sc~we Research Group Anita McC~mntql, Geophysics attd Gamma.chef- 'Extreme Ultra-Violet Absorption Cross-Sec- National Museums of Scotland ,sin:Cataloc, ue ~f lhe Scwnce Museum Collechon tions in the Earth's Upper Atmosphere', Cimmbers Street (hmd~m, 1981), pp. I-8; also d~.~cnbed in Planetary Space Sclence,20 (1972), pp. 161-164. Edinburgh EHI 1JF Cambridge Sc~enhfic ln.,4rument Company, See also NASA Press Release No: 69-112. L~st No 42: Phuslcal Instrunwnts (Cambndge, I'~61, p 63. 18 NMS.T.1998.98: purchased. A.D. Morrison-Low is b. Jenni Calder (ed.), The Wealtht~f a Natam in 19. Ernst I~,itz GMBH D-6330 Wetzlar, MM 6 Senior Principal Curator; the Nathmal Mum'urns of Scothmd (Edinburgh Wid~eld Metalh~, raphic Micn~'ope: lnstructams Dr Nuttall and Dr Simpson and Gla.~gow, 19~91, p 127. (n.d., n.p.), 32pp. are both Research Fellou~.

28 Bulletin of the ~'ientif~ Instrument Society. No. 63 (19991 The Electron Discovered, 1897- J.J. Thomson's Apparatus

Alan Q. Morton

ctn~lihons under which the cathode rays were produced, he suggested that they were fundamental constituents of all matter. These particles later became known as "electrons"; it is this work of J.J.Thoms,n's which is referred to by the phra,,e "the discovery of the electron".~

Displayed in the exhibition was a catht~e ray tube (Fig. 1) that had come to the Science Museum from Thom~m himself in 1901. In the Jubilee exhibition in 1947 the tube was described as,

The ongmal tube used by J.J.Th~nn~m to measure elm (the ratioof charge to mass) for cathi~le rays.,. ~

What the exhibition provided was a very :/ clear link between a umque event, the discovery of the electron, and a unique object, a particular cathode ray tube u.',~l Fig. 1 Hmm~n~ catturle ray tube, inv. no. lS~)14J05l. Courtesy SSPL. by Thomson. Now many different ac- counts of the origins of the electron are possible and indeed many have been A commonplace of physics textboolcs is we see how one of Thomson's cathode suggested over the years. But by looking that J.J. Thomson discovered the electron ray tubes was displayed over the years. at the ways in which this tube was in the course of one experiment in 1897. This cathode ray tube is in the collections described and displayed before 1947 we The text by Halliday and Resnick gives a of the Science Museum, London. The begin to understand why this account of typical account: conventional account of the discovery of discovery of the electron became the the electron was well established by 1947 conventional account. We also gain in- in 1897 JJ.Thom.,~m, working at the Ca- for there was an exhibition to mark the sights into the significance of the work of vendish Laboratory in Cambridge, mea- electron's Jubilee. The catalogue describ- a group of professional scientists, the sured the ratio of the charge e of the ing the events of fifty years earlier in the physicists, for wider stxiety in the early electron to its mass m by ob~rving its following terms: part of this century. deflection in combined electric and mag- netic fields. ]'he discovery of the elecln~n ks In 1924 this tube was displayed in the usually said to date from this historic J.J.Thom~m, working in the Cavendish Exhibition of Pure Science at the British experiment.../ Laboratory, Cambndge. discovered in 1897 that cathode rays, which are produced Empire Exhibition held at Wembley (Fig. when an electric di~harge Passes through 2). Here was the first occasion this But why was this experiment of Thom- a gas at a very. low pressure, consisted of particular tube was linked explicitly to son's singled out in this way? For negatively charged particles smaller than the discovery of the electron. The label histonans of scientific instruments, inter- the smallest atom known; and since they accompanying the tube was written by esting light is shed on this question when apeared to be the same whatever the Thomson himself, it said:

' + 7 I. I.P° J ,'7 , . --....I

Fig. 2 Thom~m's postcant requesting loan of this cathode ray tube Jbr display in the British Empire Exhibition. Courtesy SSPI,.

Bulletin of tbe Soentific Instrument Stx-iety No. 6.'4 (I~09) 29 a ~.pparatu- b~, which tl'~, v~P,teno., ot an m~ ~.~blu entltv, the electron ( ;i~ en the 1.47" I,ml.~ru 1~4,'~ (London tl'~' In.,htuh, of ,..-. tr,,n- ~,*,a,., d,ett'~ttx~] and tl~,~r ma,.- and reqmrument to dm elop an exh,b~t=on tot I'h~.lc., 1.47t, p. ', t '1, ,,~ ItS, mt'a,,uD.-d ' the ~eneral pubhc, ~t ,. not ~urpr=-mR "~ IbM ||ov.v~er. later on tl~, ~atah,gm. ~,. not th,t~e~er. ['~'tore =t ~a, ,ho~ n at ~.~.t'mb- that the hl.~toncal account i- ,,lmpl,tmd ,|uRe ,.o ,:atelb,ncal tor it ,tab'., '( ~. ,,! the h'~ th=- tu~' had b~'en d=~pla}¢~l at the and one oblect .*'lecttx| to ~,mbol,~' that actual tt,~.-, u.~'d b~ I I lhom~,n m th,~, ~=¢.11ct. Mu,,,.um but w~th a dttterent epi..~.ie m the hi',to~ of ph}..~c,. (;11,e11 expvrlment', t~..~hown ' In tart Ih,,m~n',, •,t,,r~ atta~ht'd rhv tu['~, wa,, not ux- the ,ntvmahonal ,~ituatlon and tht' h~tl- 1~7 papvr reporhn~ thv.,v vxl.~'rlmvnt,, make-, dear h~' u-.cd a ,~'r~ ~, ot tll|~t'~ h,r hv h=,k paln,~ pikitl~ hnkoJ h, the electron for the card ht'. tmvard, (,vrmanv ~h,,~vn b~' p~,ple m Britain at that hme, ~t I~ a].~* under- h, u.,~' ~ath~J¢", made tr,,m ditt,.rent m,m'r~al,, next t,, the obt~'ct onh. ,,tared =t had be~'n h, .ho~s that the pro[,~.rtlt'~ ot the parhch~, he ~tandabh, ~hv ~t ,,. an oblt~t ~ ith ~trong u',~'d b~, lhom~m to mea,,ure the ~eh..-d~ detected emitted b~, th,'~' ~ath~Je~ d,d not ,,t the ~ath~'~h' ra~,. and ol the raho rn e Br|U-h conno:tlon- that ~ u,,oJ and the de|~.,nd on the mater~al ot the ~athi~h, rvh,~ant work m (,erman~ completel~ l~'lorv I~24 thp. tub~' ~ de.~ntx'd a. an ~,nort~l 4 11 Fhom,.,,n ,irran~.ed to borrow thl*, tub,. m,~trumt,nt for makln~ mea.,urement., o11 trom tht' ~wnce %lu.eum Ih' wrote to ~athode raw lhere ~a,. 11o cxpl,ot [he~' rua.~m., coupled with lhom..on% Lolond l~.on-, the I)m.ctor ot thv .~u.nce menhon of ih~, d;.~,,~ vr~ ,,f tht' ek~-tron ~..ork on the elt~.'tron make the pared Mu,~.um. 'I have b~.n a,.ked to vxh,b~t at ~,~,vmhh,~ the apparatu., I u,~'d in my flr,,t lh,~mer, the m~,a-urvment., made ~th down account that he d~mered tht' ex~,r=ment,, on the vh,ctron dt,,~-rd~,d I the tub~' could, ,n a ..~.parate ~tep, be t, ie~tron I11 the cour,.~' ot one t, xr~,rlment belu,~e a,, apparatu,, for determ,nml~ the lntvr~rvtt~| a,, demon-tratm~ the ex~,,- m l,~q7, the comentional account re- ~vh~-it~, and the ~ah,e of e~m for cath,~le tenet' of the' electron pvatoJ i11 ph~-ic, textbt~k', t,~Jav. raw' %, m Iu24 lhom~m ,,aw hi~ earlier exl~.,r=mvnt', a~ bvm~ to do ,.vdh ek'clron~ At the t~me ot the Bnt,~h Empm' ~rather than the 'u~rpu,,~h,,J m. he had or0~m- l-lxhlbmon in I~24. ho~ve~er, the account Notes and References all,, calks| them) of thorn.on, work had been Eared 1 D Halhda~, and R Re,.mck, I'hu.~. INt'~ do~vn and -m~pl,hoJ until the device Author'~ addre,~s: ~ork %%tim, 1'.~ i'art II, p ,~1": hi'corot-, the tubv u.~'d t,,r the exix, n- ~Clt'tlt'(' ,~ll~,~'llt~l merit The artefact ~a,, nmv the t~r',t 2 D II |~,lh'tt. lt:, I h',tn,~ l.l'd*'c I dul,a,,n S,,utlt Kensm,~,,ton dt'~ Ice u,,~'d for detectm)z, the exP, tellce of I,,¢,!,I at tth ";,, l,'~I,,' '~ft~.,':~,tt [_otz,h,,t '4¢'ptt'mhcr Lon,hm SW7 2DD

" Xmas Rays

l he urchin of thi.. I~)~ I:.~-tcard ix ~tartled to .,~'e his Chn..tma. pudding ~.how ti E by thi,. mv~.terious beam. Hv tear,, that ~'cret nnpromptt, ~nacking can no hmger be kept .~'cret from hi., mum By now Rontgen's x-rays may ,.till only be .~,ven ~ears old and their physics not g1" generally under.,t¢~J but, as indicated by this popular po.,tcard, their >igllificance was already well appre- l ciated by the public at large.

:t

The Editor extends, on I~,half of the SIS Committee, a very harpy Chn,~tmas and New Year to SIS members. May you all enjoy the ft.'stivitk.'~ as much as the little b,n,; ¢~n this card.

~l Bulh,tm of the .~'ienhf|c Im, trument .~'WO,' No. 03 (IN) The Spinthariscope The Instrument of William Crookes that Made Alpha Particles Visible H. C. Bolton and J. R. Patterson

t

Fig. ! The 5l,mtharisc,,pe with the name W. Cr,~,k,'s and tit; dat; 1903 inscribed. Tit; two Fig. 2 Cn,,kes' spmthariscope sir,wine tilt, maker, W. Wat~,n & Sons, 31.3 tll¢h Holh,rn, W small screws hoht the brass b~h/ t,, the C (h,l,fim UKL The original t,lack h'ather ca~" has a h~bel with catah~¢ue numl,er and r~,m~ eb,,nih" base. Thelt were r,'moped to rel,lace hration, fir' latter dating from 1926. The kmtrh'd wheel ~s att,~ched to tilt' scn'w D m F~,¢. 3. th; t,ho~l,lr,r. The mstru,r'nt is on ,tisph~y m the Physics Museum of tilt' Umz~'rstty of A,h'laMe.

The spinthari~ope is a small ~ientific Another report' on ~,ptember 20, 1903 in covered by the darkening of photo- instrument that was familiar to th~. the Scientific Australhm magazine gave graphic plate~, was published m a ~,nes working in the field of radioactivity after substantiailv the information above, with of f~ pape~ in 11,1% by A H Bequerel 1~13. We comment on its significance in the additi~;n that the maker was the (It~52-1~lSL" In l~l-i, in his annual report the hi..,torv of ~ience and report on one chemist Sir William Crookes {1832- to the Chemical ~,ciety ;', Frederick which was left in Adelaide by W.H Bragg 1919). An adverti~ment in Dt~:ember Soddv (lS~-lq%) comments that the on his departure, as EIder'i'rofts~,r of from Watson & Sons had the infi,rmation phosphort.~ence of zinc sulphide under Mathematics and Experimental I'hvsics in that the instrument was 'to hand', price the ~t-radiations was di.~ox'ered ..,imulta- 19(18. '1903' is the year in~ribed ,~n this 30 shillings (£1-10-0). ' By the middle of neoush" by Cr¢~kt~ and by Elster and instrument shown in Fig. 1, under 1904 the firm started advt, rtising for it at Geitel'wfio were investi~atin~ radio- St,mtharis,,,t,e and W. Cn~,k,'s. a rtxtuced pnce' : activity in air under, round

The sto~' in Australia of the .spinthari- Radium. Supplies of this rare dement ot the ]'he earh,' worker~ in radioactixltv, in highest radioactivity now on hand Applica- .~-ope starts with the newspaper adver- attempting to under.,,tand the m, tonlshln~ ti~,ment in August, lq03~: tions for u~' ;n therapeuhc ~ork I'rof Crtx~ke's (sic) Splnthar~'ope, to sho~" the new re~vlts of their ex|~,riments, were .Me,,srs W. ~Vat~,n and .%~ns of S~,anston St activity of radium: £1-5-0 faced with the ditficultv that the~, could IMelboume] have lust rtx't.ixt,d from En~- only interpret the~' results bv a~sun'un~, land an interesting little instrument known The meaning of the word 'maker' is that that the atoms thev were examining, such as the spmthari~-ope, cont,unmg a .small Cn,,kt.,s was the dt~igner and no doubt as tht~.~' of radium and uramum, mu,,t quantfly of the rtxentlv di~'ox'ert~l sub- maker of the prototype. The commercial have the property that they txert' not stance radium. ]he instrument demon- maker was William Wat.~n & ~ns, a stable but were ct~ntmuouslx"dlsmte~rat- strafes the extraordinary physical maker of ~ientific instruments in I.on- ing and emitting atomic particle-, ~mce, protx, rtlt~, of radmm, the rays or atoms don which started in 1837: its branch in according to ~.fdv', the quanhtv ot ~p,t.n out being rendertx| xisi~le in a ve~' radium m, ed in a spintharlscope i,, str, km~ manner, a ~cmtillating appearance Melbourne, Australia, was opened in bem~ observed as if a number of mim,te 1888/The name W. Watson & %has, 313 'probably unwt,ighable, and =t~ effect sparks were contlntlOtlsly ~.,lng thrown off High Holborn (St London) W.C. is al.~ I.'~,rslsts over years wflhout dmunution. by the substance, this is probably the first in~'rit'~.d on our in.,trument, as shown in although the~'reen may need to |'~, lntn~|uction of radmm into Australia. Fig. 2. It is possible that Crt~kt,'s may replaco.|, .,,ome idea nl,l'c be obtained ot have suppliecl the radium ~mrce. lh~, the delicacv of the radioactive meth~|,, of On ~'ptember 5, Th,' Austnflaslan news- advertisement suggests that 'Watsons mvt~tigati~m'. paper: contained a report of the tirst may have u.,~.d the popularity of the public demonstration of radium in Aus- spinthariscope to promote future ~]es of The early confu,,ion in the .',tudie,, of tralia at the Royal Society's 'Conver~- radium fi~r therapeutic purpo~'s. ~ radioacti{e atoms was neatly expre.,,,,,~.t zione'. A small ~iuantity of radium was in the first description of the three mounted in a spinthari~ope; the public Sir William ('n~kt.,s was well known fi~r different kinds of ellli~,siofl a~, alpha, beta was invikxt to view the flickering alpha his work on eltx'trical di.~'harg¢.'s and as and gamma, the first three letters of the particle .~'intillations on a zinc sulphide the di.,~'overer of cath~.te rays in 1870. (.;reek alphabet, and .~hll u~'d. Cn~,k¢'~. ~reen prt.'sented in a micn~cope field The radioactivity of uranium ~flts, dis- in a i~t13 article '~, used the phra,,e

Bulh,tin of the .C,clentific Instrument ~cietv No. 63 (]gqq) 3| .,,peck of radium a ~hort distance off a zinc Other means existed for the measure- sulphide screen, and exam,m'd the resulting ment of the ionisation produced by alpha fluorescent light with a magnih,'tng k,fls. He particles. For example, in 1904 in Ade- found that the fluorescence did not pn~,ed umformly from all parts of the screen, but . hide, W. H. Bragg at (1862-1942) used a that it came from i.~dated points dottod thin (3 ram) ioni~tion chamber with a about on the .,,urface ...This appearance is metal gauze window and potential only pn~duced by the ~-rays.... The simple difference of I00 volts across it, and and din~-t interpn'tationof the luminous measured small electric currents with an specks L~ that each speck corre~n~nds to the electrometer to show the increase in ion impad of an a-partk'le. density towards the end of the tracks and the existence of several different alpha However, Strutt also considers the possi- groups from the source. '7 The Wilr,~n bility that only some :t-rays may emit cloud chamber, developed earlier, was flasl~es from crystal defects.'This appears used to make alpha and other tracks to have been ruled out over the following visible in air from 1911J' In his first few years. report of tracks, Wil~m used 'a radium- tipped metal tongue from a spinthari- I) ~ B The Greek word for flash or scintillation scope' as his ~ source. An electronic was used by Crookes in his word counting instrument, first mentioned in spinthart.~'ope. Cn~)kes gave at the end Rutherford and Geiger's 1908 article, was m, i!!i i of his article" a Greek quotation from 'rediscovered' in the Geiger-Miiller coun- Homer's Hymn to At,,llo. The translation ter '~ in 1928 and used initially in cosmic is: 'Then like a star at noonday, the [a,rd, ray experiments. far-working Apollo, leaped from the ship: Flashes of Fire flew from him thick The story of the spinthariscope in and their brightness reached to the Australia continues with Frederick Sod- heaven'1 ~, dr. After his work with Rutherford on the physics of radioactivity, he returned to Fig. 3 Vertic, d cn,ss-~'ction i,f a slmih~r In the same iournal under Proceedings of University College, London, where he des~Cn, adapted from tlw dia~,n~m in tit,. &~,k Societies, is a brief description of the worked with Sir William Ramsay in the bu F. S~t, tu, The Interpretation of Radium. 'Conversazione' of the Royal Society of Chemistry Department. In 1904 he ac- /1 is a iwedh' carrym.~ a small speck ,ff London of 15 May 1903 in the presence of cepted a Lectureship in Physical Chem- radium: B. the ph,)sph,,res,ent :me sult,hi,[e HRH the Prince ~f Wales": istry and Radioactivity at the University .~'r,'en; C, th," m,~gn!~in S lens; D, a kn,,b of Glasgow and in between leaving pr,,tectmg ,,uts,fe the l,n~ss tub," and attached Sir William Cn~*kl~ showed some experi- Ramsay and taking up the apl~intment , t0 a .~r~e a,h~ch raL.~s and h,u~'rs the lu'edle ments illustrating the prol~,rties of the he paid a visit to Australia. He had been A and rotat,~ # ~ro,n side to side. The inside emanations of radmm: invited to give six extension lectures in wall :s blackene, t to avoid r~. li'ctions. Perth, Western Australia; he accepted Auto-radiographs of Thorium, Uranium and was welcomed enthusiasticallyY 'Emanations of Radium' in his title, but and Radium minerals. The people attending Soddy's lectures he did not u.,.e the Greek notation fl,r the in Perth had no doubt read of the new scientific work on radioactive substances three emanations. His description is as 2 l'hotograph~ of Radium Emanations follos~'s: Lh-flt~'tahle and N,m-deflectable by mag- m,rstly in the newspapers, but S(~dy netism brought demonstrations with him which The vmanatu~n~ are of three kinds (.)r~. ~et included the display of mineral fluores- cence under the collisions with the 1~ the .,,anne as the cath,~le >tream. now 3 Radiographs of a clo~l ca~ of instru- ~dcnhtied with free electrons ...; the beta ments ... radium rays. Several spinthariscopes part~ck~ were passed round the audience who could then 'see the dancing display of Another ~'t of emanation.,, trom radium are 4 Luminous Effects of Radium Emana- scintillations'. :j not atfected by an ordinardv powerful tions ... magnetic held, and are mcapabk, of passing through xerv thin matenal obstructions: the 5 Photographed Spectrum of Radium After the lectures, S(~ldy travelled to alpha partich-,, hehum nuclei. Adelaide by ship, arriving there on A thmt kind of emanation is al.,~ pn'~luced 6 The Spinthari,,,cope. Sunday 31 July 1904 and left on the next by radmm B~'~ide~ the highly penetrating day. Soddy's visit was the day after W. H. raw ,h~ch art. defied'ted by a magnet, the~ Bragg began his radium experiments, are other }*~'netratmgrays'which are not at A diagram of the instrument is illustrated referred to above. Soddy stayed with all atfect~t by magnetism. Th¢~-.e are ... in Fig. 3, adapted from figure 10 in the Bragg to whom their meeting was of Rontgen rays: the gamma rays. book by Frederick Soddy ~' and the reat help; Jenkin shows how Bragg's photographs of the 'Bragg spinthari- rmer difficulties about getting his The article just mentioned contains the scope' in Figs l and 2 are of a very research articles published in British earliest reference we have found to the similar design, it is a small demonstra- journals were virtually removed by spinthan~ope. There appears to be no lion model. The scintillations seen in the Soddy. "~ There is every reason to expect specific publication by Crookes of his zinc sulphide screen could be counted to that Soddy gave or sold one of the imention. R J. Strutt'noh.,s in his 1904 make quantitative observations of indi- spinthari~opes to Bragg on that exciting book ?'/I," Be,luerel Rays and the Pr,,pertws vidual particles. This was tedious to do; Sunday. As the cost quoted in S(~dy's o¢ Radium': that the time of observation and measurement book" is 'a few shillings' (p. 59, but see was about half an hour and that needed a ref. 4), it is likely to have been a gift, in Crooke,; has made a very interesting spell in darkness to allow the eye to repayment of hospitality. There Ls no t~,natlon on the phlr,ph,;re,,cence pn~- adapt it~lf fi~r counting the scintilla- duced by the z-rays. He brought a tiny lions. '~ record at the University of a purchase from Watson's. Bragg would probably

32 Bulletin of the ~wmhfic Instrument S~K'iety No. 63 0999) have used it in lecture demonstratioRs, Acknowledsements for which he was well known. 16. Personal reminiscences from the late Professor L.F. Bates FRS of the Physics Our thanks are due to Mike Williams of The instrument shown in the photo- Department, Nottingham University, UK. the History Department of Monash 'L.F. Bates', Baa~raphecal Memmrs of Fellous of graphs stands 40 mm high and is 25 University for drawing our attention to the R .m~alSociety of London, 29 (1983), pp.l-26, mm in diameter. ]t has a black leather the item in the Argus newspaper of by Nicholas Kurti. container as shown in Fig. 2. It appears in reference 1, John Prescott for assisting the oldest Physics Department catalogue 17. W. H. Bragg, 'On the lon~ation of Vanous with the refurbishment of the spinthari- Gases by the Alpha Particles of Radium No 2' as number 982. Its provenance to Bragg scope and use of his alpha counting Tran~ctions of the R(nlal Soc. of South Austraha, was well known as attested to by Sir system for tests, John Jenkin for reading 30 (1906), pp. ]-22 , plus Plate Vii, for a Mark O]iphant, a 1923 physics graduate the paper and providing helpful refer- drawing of this beautiful apparatus built by A and S.A. Governor, who was asked to ences and comments, including advice on L. Rogers. See also Phil. Ma£. Set. 6, 13 (1907), identify it in a 1976 Summer School panel Bragg's acquisition of the instrument. Plate IX opp. p. 332, and following article: pp. discussion. The catalogue 2~ is an alpha- RW. Home was also consulted on this 33~357, and W. H Bragg and R. D. Kleeman, betical list of lecture demonstration and matter. Alan Ewart, the former curator of 'On the lomsation Curves o4 Radium', Phil. Mac. Set. 6, $ (1905), pp. 726-738. teaching apparatus which appears to the Physics Museum, and Harry Medlin date from about 1909. it was probably are thanked for helpful information on 18. C.T.R Wilson, 'Condensation of Water prepared by Bragg's technician, A.L. the catalogues. The Education Technol- Vapour in the Presence of Dust-frt~ Air and Rogers who retired in 1927. He may ogy Unit at Adelaide University is other Gases', Phil. Trans. Rail. Soc. land., A, IM have started the gold labels seen in Fig. 2, thanked for the photographs. (IPRT), pp. 265-307. The first particle tracks are which were continued by Arthur Shep- reported in 'On a Method of Making VL~ible pard, laboratory assistant to Professor Notes and References the Pati~ of ionising Particles through a Gas', Kerr Grant, who succeeded Bragg in PnJc. Roy.. Sot'./.and., A, 115 (1911), pp. 2.85-28S and Plate 9. 1909. He may have requested the I. The Argus newspaper, Melb(vdrne, 19 Au- catalogue. The location: Room 114, gust 1903. 19. HGeiger and W.Mtdler, '[:)as Elektronen- appears to refer to the current Physics 2. The Australasian newspaper, Melbourne, 5 zahlrohr' (the electron number-counter). Phys. building which dates from 1926, so the September 1903. Zeit., 29 (1928), pp. 839-841. This is an labels may date from then. unproved design. Set, aL~o the first reference 3. The Sc,ent!~c Austrahan, 20 September 1903, in E. Rutherford and H. Geiger, Pr0c. Roy.. Sac., A recent measurement shows that the p. 6. A, 81 (1908), p. 141. radioactivity level in the instrument is 4. The Scientific Austrahan, 20 December 1903, 20. John G. Jenkin 'Frederick Soddy's 19o4 about five times nn)m background. The p. 22 of advertisements. visit to Australia and the subsequent Soddy- phosphor has deteriorated greatly since 5. The Scientific Australian, 20 June 1904, p. 66 Bragg ctwres~mdence:. Isolation from Without 1903, resulting in very low intensity of advertisements. and Within', Historical Records of Austrahan scintillations at a rate of -0.8 min-' as Scwnc¢, 6 (2) (December, 1985), pp. 15~i69. 6. Glm'ia C. Clifton Directory ofBriti~ Scient#:ic measured on an alpha counting system. The spinthanscope is mentioned in his lectures Instrument Makers 1550 - 1851 (1995 reprmt~ in Perth on pp.160, 161. The instrument was taken apart by 1996) Nati{mal Mantime Museum, Greenwich, removing the two small screws in the UK. 21. Jenkin, reference 20, p. 160. bakelite base, and the old phosphor, 22. Jenkin, reference 20, pp. 163 164. which appeared to be deposited on 7. H.C. I~ikm & Nicola H. Williams 'Scwntific Instrument Makers and Dealers in Victoria, cardboard glued to the base with gum 23. The official Umversitv catalogue was made 1840 - 1914' Historical Records of Australian by Ms Pamela Runge m 1986, based im the dd Arabic, was temporarily replaced by a Science 12 (1) 0une 1998), pp. 15 - 82. catalogue. doublPhosphorfresh screen" fastened with sided tape to the base, resulting 8. H. Hamersley, 'Radiation Science and 24. J.M. Woithe & J.R. Prescott, 'Effictenctes otr Australian Medicine 1896-1~14', Htstorical Re- Phosphor Screens used in Thick Source Alpha in greatly improved performance. In a cords of Australian Scwnce $ (3) (1982), pp. 41- dark room one can easily see a diffuse Particle Counting', Ancient TL, 13 (I) (1995), 63. pp.10-15. glow mottled by fluctuations. The mea- sured count rate improved to -100 s" 9. A H. Bequerel, Gm~ptes Rendus de I'Academie 2-=;. L.F. Bates & J.S. Rogers 'Particlesof Long des Sciences, 122 (18%), pp. 420, 501, 5~, 68~, The rate can be slowed by adjusting the Range Emitted by the Active Lk,l~its ot 762, 1086. An accessible (Engl.) account with Radium ]'honum and Actinium', Pn~'. Rat/. height of the metal tongue carrying the illustrations is his 1903 Nl~hel Prize lecture. source. S,r. Lond., A 10=3 (1924), pp. 97-I16 L.F. Bates M~6el Lectures in Ph~ics 1.~I-1921, (Amster- & J.S. Rogers 'Particlesof Long Range from As a final comment, we believe that the dam: Ei.,~evier Press, 1967). Polonium', Prtr. Rcn/. S,~'.Lond, A 10S lI'~24), last research work using the technique of 10. E S~ldy Annual Pn~ress Reparf h~ Chema'al pp. 360,~0. Rogers' work m the 193~-45 war Ls visibly counting the scintillations was Society 1904, vol. 1 (1905), pp. 244- 280, described m: H.C. I~)lhm, 'Optical Instruments that by L.E Bates (1897-1978) and J.S. reproduced in T. J. Yrenn, Rad~(~ctn.#v and in Australia in the 193q-45 War: Successes and I~'~ Oplx~rtunities' , Austrahan Phusicist, 27 (3) Rogers (1873-1977) whilst research stu- At(nnic The~ny (Lond(m: Taylor and Francis, 1975), p. 64. (199o), pp 31-4,1. dents under Rutherford at the Cavendish Laboratory, Cambridge in 1924/" Radia- 11. William Cre~kes 'Certain Pr~q3ertiesof the 26. R. Ho~tadter, 'Alkali Halide Scintillation tions of all types were found to cause Emanations of Radium', Chemical Ne~=s, 87 no. Counters', Php. Rev., 74 (1948). pp. 100-101. and 'The Detection of Gamma Rays with scintillatim~s in a wide range of materials, 2269 (22 May 1903), p.241. Thallium Activated Scdium k~ide (~O,stals', organic and inorganic. The materials are 12. R. J. Strutt, The Bequerel Raus and the Phys. Rev., 75 (1949), pp. 796-810. usually called phosphors. As an example, Pnq~erties of Radmm', (Ltmdon: Edward Ar- in 1948, crystals of sodium iodide nold, 1904), pp. 81-82. 27. H. E. lama and B. Salzber~, 'The ~Kia~. Emission Phototuhe', Par. IRE, 23 (1935), I~. activated with thallium were found to 13. H(nner, 'Hymn to Apollo', Hesa~d: the 55-64. be efficient detectors of gamma radia- Homeric Hymns, Engl. translation by HG. tion. ~ The method of detection uses a Evelyn-White (Cambridge, MA., Han, ard Uni- Authors" addres,q,s: photo-multiplier tube ~ developed before versity Press, !"4 ed. 1914, latest1%7), lines440 H.C. Bolhm Htsto~ and Phih~)phy ~ the war, for converting the scintillation 442. See also tel 11. Department of into a voltage pulse. This detector has a Science 14. Anon. 'Conversazhme of Royal S~'iety of Uni~crsi~ ~. Melbou,te, Australia 3052 higher efficiency for gamma rays than the Lond(~n" Chemical Neus, $7 (1903), p. 24~. ].R. Patterson Department t~ Physics and Geiger-MiJller counter and has largely 15. E Soddy, The lnterpretatwn of Radium superseded it. Mathematical Phusics (London: John Murray, 19O9), pp. 59-62. Unizrrsi~ of Adelaide, Australia ~1,5

Bulletin of the Scientific ~t S(x'ie~ No. 6,1 (1999) 33 Lovell Radio Telescope at Jodrell Bank

Kevin Johnson

funded pm~

As approved, the radio telt.'scope con- sistt~.J of a 77 metres" radio dish that moved vertically in a framework that in turn rotated horizontally. To reduce costs the vertical I~,arings were fi~rmed from two 26-cm gun turret racks salvaged from scrapped battleships. To track celestial obiects using an altazimuth design it was necessary to simulta- neously drive two axes at continually varying rates. The challenge was over- come by employing analogue techniques consisting of magslip resa,lvers m a servo k,,p.' Other pr,~lems included the need to support a load of over 2,000 tonnes on a central pivot and circular track, yet move it with silky sm,~,thness to arc minute accuracy. Likewi~, the radio dish could flex no more than 50 mm as it is moved from the zenith to the horizontal. Common to many large science proiects, costs ~on escalated to £41)0,000, a short- fall that was bridged by a grant from the Fng. 1 The Iodrell B, utk r,z,/w t,'h'~o,t,e, 5 l-el,ruaru l~loo Courtesu Nuffield Foundation. Certain mcrea.,~s 551'l. were due to inflation while others were caused by changes in design specifica- A, a pumeer in radio astronomy the Department h~r Scientific and Industrial tion. Significant amongst these was i_ovell Radio tele~ope has attained iconic Research (DSIR) who gave an initial discover, of radio emissions at a wave- -tatu.,. a metaphor for 'Big Science'. A grant of t227"),140. Although being a time length of 21 cm cau.,~:t by molecular prominence made more .~ignificant in of general austerity, the costly ~heme hydrogen in interstellar space. For detec- hght of It.', prolongtxt and troubled birth. was quickly approved as a nationalh," tion the tele~'ope needed to work at

[k.mard lowell entered radio astronomy through h,. attempts m 1~4 =, to dettx:t co-,mic rav~, u~,nng ,,urplus wart=me radar eqmpment Ba~'d at Jodrell Bank in Lhe.,hm' at the botany oub, tation of Mancht..,ter t.mxer~,itv, his initial efforts ~ere un.,,ucces~,ful. In~,tead he deteckx| the umL~xI trail,, of meteors as they bum up m the upper atmo,phere.' Lovell rt'-,t'arch h~'u,, ~n changed and by 1~47 wflh only ¢I,0(X~ he had constructt~ a radu~ trans,i lele',~'t,pe with ,1 ~ire dish aerual, h7 mvtre~ acro,s. [he radio rtxt'l~.er ~xas mounted alott a 3q-metre pole which could be mo~ed using guy nile,, to ~i~.e hmfled pointing.: 5tlCCt'~,s ~vJth this new instrument ,,purred I.mell to draw up plans for a fully ~tet.rabk, radu~ tele,,cope ~lth a 77,-n:~etre para- boloid refltx'tor Dvspite support from his umxer-flv nt was not until 1'~49 that Fig. 2 ~,w,,' *'t ttw Iodrcll B, ml, (ontr,,I Room ou J2 ( )~ tot,or 10~,,~, x nable pl,ms emerged when the engineer nu,mt0rm£ the pr0,cress of I'ione,'r I. Tit; first, but alas unsm'cesshd ttC Itu,band Iolno.| the proiect. The atteml,t by the Americans to sent a st,ac,.,:ra fl to the Mm,n. C,,urt,'sv prototype design was then taken to the 5SPl.. " "

?~ Built,tin of the .~-|entific Instrument .~.'ieW No. 0.11 (i~) much shorter wavelengths than first craft and confirm its landing on the Notes and Reference~ anticipated. In con.~'quence, the radio surface of Venus. reflector originally specified as copper 1. B. Lovell, Vmce of wire had to be changed to a solid metal the Umver~ (Lmidon, Since its completion in 1957, the Mark 1 19R7), pp. 1-3. dish." Although well under construction Jodrell Bank Radio Telescope has been a by 19M, its budget had by then further 2. B. Lovell, The Sto~ of Je4trell Bank (London. powerful research tool in radio astron- spiraled to £700,000. Despite special 1968), pp. 16-18. omy. it has been continually updated and pleading by Lovell, the DSIR would only from an early stage was equipped with 3. "J. Agar, 'Making a Meal of the Big Dish: fund half the increased costs with the digital computers to drive the telescope The Cons~ of the Jt~iwll Bank Mark 1 balance coming from [x~rd Nuffield and and process its data. Likewi~, the Radio Telescope as a Stable Edifice', Bnhsh Iournal fm the Histonl of Scwnce, 27 (19~4), p. 6. other local sources after completion (Fig. strengthening of the telescope framework 1). I~'devilled by financial crisis, the radio and the construction of a new more 4. B. lxwell, The Sto~ of fl~drell Bank (Londtm, telescope shot to prominence in 1957 accurate reflector over the original dish 1968), pp. 59-6O. with the launch of Sputnik. It was the has increased its power and sensitivity. 5. Ibid.,p. 7. only instrument then available capable of Now called the i.xwell Radio Telescope, it tracking the carrier rocket that lofted the is currently used as the main component 6. B. Lovell (note 2), pp. 189-194. Russian space png-~e.~ Later it gained of a large radio interferometer called similar publicity when if transmitted MERLIN [Multi-Element Radio-Linked 7. B. [zwell (note I ), pp. 279-281. command signals to Pioneer 5 the first Interferometer Network]/ In spite of its Author ~ address: successful American deep space pn~e age, the telescope is still at the cutting Science Museum (Fig. 2). It was likewise used to detect edge of radio asm~nomy, a field it first South Kensington signals from the Russian Venera space- blazed a trail nearly four decades ago. London SW7 2DD

Market Place of 20 th Century Instruments

Desmond Squire

In this review of the market place for twentieth ft~r tht~e instruments that have made the plating for the knobs and other small fittings. century scientific instruments i have concen- transition from the 19" to 20~ century. Items A grey finLsh comes in to replace black in the trated on those items that I have had some like sextants, theodolites, microscopes and 1960". Finally at the end of the century the experience in dealing with. The ones that I demonstration equipment are sought after. microscope is finished in white ancl the have covered are those that tradi~mally fall There are fewer collectors k~king for late controls am made of cmnposite materials. within the remit of the Scientific Instrument 20~ century instruments. They are pe~le who The m(dern micnw~op¢ is no innger just an Society, whether they are their 20~ century either use the instruments or have an under- (~tical assembly. Computers, lasers and image replacements or those that newly appeared in standing of their historical development. They. capture devices have been added to provide the 20~ century. are less interested in collecting them solely [or sophistk'ated image analysis and enhance- their appearance. merit. Ahmg with other areas of science and technology there have been more changes in Each type of instrument has gone through an In the following section l have ne~'iewed the the field of soentific instruments in the 20~ ewflution throughout the century. Some current market place for those scientific century than in all the previous ones. In 1900 changes were dramatic, for example, the u~truments that appean,d m this centun' scientific instruments were little different in aviation and submarine sextants used in and a couple Of those that ceased pngluction. appearance to their predecesca)rs. They may World War [I although functiCmally equivalent I have concentrated on th~x~e that I have have been more accurate, better made, easier to those of the 19~ century look nothing like experience of dealing in. to use but they looked and felt like instru- the traditional sextant. Some evolved more ments from the previous centuries. The slowly the instruments and apparatus used in Mechanical Cak'ulatms intrlductinn of electr~mics and digital compu- schools and colleges in the UK were being ters for both the operation of and design of made with traditional materials such as These were pn~uced well into the 20'~ instruments has resulted in radical changes in polished mahogany, lacquered brass and century, they were made ob~dete by the fi)rm and functionalily. Micro-miniature com- cotton covered wire up to the 196ff. The cieskt(~ and i~cket electromc calculators that puters have enabled instruments to be de- greatest changes have bt~n in last 30 years or were produced m the 1960" and later on by personal computers. There Is a sm~ng mte~t signed that previously could not have existed. so with the intrt~ucfion of electronics and The sensors that detect the physical phen(nn- micnvrocessors. in collecting the very. wide range of these ena grow smaller, the interpretation and calculators, even the once spurned grey painted Facif calculators ot the 197{~" are now presentation of the data is done on a computer. The change in appearance and design collected One of the n~st popular mechanical throughout the first 70 years of this century The market place for 21~ century instruments has been a gradual one. For calculators is the Curta, admired for its example, English intricacy and precisi(m. It is m is dependent up~m what part of the century microscopes came into the 190(P c~n~strucledof portable, sits the hand and is visually attractive, h~kmg like they originate from. Pre-World War ii instru- lacquered brass with part fitting in a dark a croc~ between a pepper mill and a hand ments, can on the whole, be ctmsidered to oxidised lacquen~d brass. There was a change have evoh,ed from those of the 19~ century. using grenade. The Curia calculator ceased pn'duc- to a black, glossy lapanning for the base tion in the 107(r. They are m)t so grand and the finish is not so and limb, the tube and knobs remained with a decorative. Prices are lower and the supply is brass finish. Later in the 1930' the Cmly part of Slide Rules more plentiful. They supply the need of those the instrument that was braes was the knobs. collectors that are new to the field or have Later still the kn~,s are nickel-plated and in Some instruments went out of pn~uchon very limited budgets. There is a strong market place the 1950' there is the introduction of chnmw "suddenly, the slide rule is a prime example.

Bulletin of the Sc~ntific Instrument Society No. 6.3 (1999) 35 The mtroducta~n of the Fx~:ket four hmctam Radiation Monitoring aad Me~uremeal Earth m with a few hundred metric. HandseO and scientific caleulator early on the 197Cr can be purcha.',x,,d [or le~ than £100. Too new wtped out a complete industry. ['here are still a Based upm the detector invented by Geiger to be collected, but within a couple of decades few H~cialist rubs made hw speciali~ situa- and Rutherford in 190~. The Geiger amnter I am sure there will be a price guide to late 20~ tams. Collecting slide rules has become a became a much used necessity atter 1945, for century GPS sets. malor area of collecting within the Pa,q 10 both military and civilian work. The instru- ment was made into a handy, practical k~4 years. Slide rule collecting t~ opp~wtunities Some Instruments are uncldlectable, such as that was Issued by varmus goverrunents by [or a very wide range of collectors. There are at those one-off designs that are put into satellites the thousand. There are semk'tmdudor detec- the m~wnent abundant supplies of plastic slide and other extra terrestrial exploration vehicles, hws m u.~e today, but many of the 1950/60 rules at low prices (£20 - t~)) that allow they are designed never to return to Earth valve based detecttws turn up for sale at k~w collectors to get started. There are plenty, of except as a fireball. middle range items, such as the fuUers and prices. There are collectors wM~ are interested Titachers rules (f.200 - £2t)1~1) for serious in items associated with the history of collectors to graduate to There are the radiation, its pmducti~m and its measurenw~t. The End of Instruments? e~teric items h'om earlier centuries that Radar occa~,mallv ctwne tmto the market. The slides IRstruments that have been created in the last rules of this century, provide an opportunity Radar came out of World War II and was used two decades are starting to kink the same- is it for tht~e collectors that en~,y collecting hw ranging and navigati(m. Earl), apparatus a scientific calculator a GPS navigator or a vanances of items. There are odlectors that was very bulky and secret. Collectors have to digital voltmeter? A glance at the casing and are k~kmg for all the rules made by ,me be content with collecting key items such as shape will not give an immediate clue. The manufacturer tw are trymg to coiled all the magnetrtms, manuals and other documenta- label or hmctkmality of the m~trument has to nditions ,4 Charles Plckworth's The SMe Rule. tam. Though ten years after the end of the war be examined to see what its purpose is. With A Prachcal Manual. the numenms government surplus sh~,s in the appearance ~ instruments c~mvergmg will Ltmdon and el~wbere had large quantities of other than institutional collecting cease? Distal Cempmm pad radar equipment for ~le, itt'~1~ssuch as Probably not, collectors vary in what they are display units and micn~wave genecators were k~oking for, some enjoy colk~ting variances of Working electronic digital ct~mputers were available. a single or similar items. The collection of devek~:~,cl m the middle ~d this centu~ They pi~ae cards and stamps are examples. wen" constructed ~wn vah'es and mechanical Radio and Wireless ct~mptments and were vt~." large. Collectors of the~ earh' d~gttal ct~pute~ hax'e tO ctmtent Radio ts predominantly used for commumca- Web tires themseh~ with fragments of machines. ti,m and br~Icasting, h~ever, it is also u..~! Whok, early ctm~puters were entwmous and in navigath~n such as in the Lh,cca and h~ran .Scientific Instrument Sq~'iety: www.sis.org.uk have bet~ dr.,-an|i'd t~x-askmailv sub-a.~em- systems and d~rection hnding, originally bias. ternte n~,mont.,s, in.~trut~n manuals known as radiogtmitwnettq's. The market place ctwne tmto the market [ have flmnd that there for these item.,; L~ slim. IR,~truments a,,~s~'iated Quekett Microscopical Club: www.nhm.a- c.uk / hosted_sites/quekett / are ready bux,q's for these items but there Is a with electnmics and wirek,,ss are collected and ..,hortage of available tlt'ms This L~ a very this Bulletin has published an article al~mt the un, tructured market As of ntx'es~tv colleck~ histo~" of the Av,nneters. Of particular interest Intemati,znal AssociaCkm of Calculator Collec- of computers are ctwa.'entrahng on the mini- are tht~e items as.~iated with military tors: ww w.geocit/es.c~m / SiliconValle/Park / computt~ hrst ~dd in the middle ,ff the 1'~60' wireless such as wavemeters and test equip 7227/ and ma'nx'omputers that were built m the ment. mMdle ot the 107it. Although nt~t the first Rocketry Directory of lnttm~et Computer History Sites: commercial microcomputt~r the Apph" 1, first http://dmoz/computets/History/ made m I'CO. is a rantv and when it has been I am olten asked for parts ~)m V! and V2 ,m the open market has hqched a price n~we mL~siles such as the uavigatkmal gyn~sc~e, than a ttne Vich~nan microsoft. The market Vintage Computer Festival: www.siconic.- though I have been unable to find any. Parts of i,w mlcn~omputers ~ well structurt~l and corn / vd/ mi.~ilt~ do up fairs and I have coik~-tor's guides wdh prk-es are published later turn at seen transparent m~sec(mes containing together with .~pet-iati~t fairs infra- red beat seeking se~rs and other pads of British Vintage Wireless Association: www.bvws.org.uk/ Pocket Calculalors rockets offered hw sale. The Eleetnm Mkroscope The llr,~t Iour-tunch~w~ calculator came tmto Antique Wireless A.ss~'la~m: www.antique- wlrele~s.org / the market m 1071 made bv S4"tarp and cost Kradl and Ruska invented the elecmm mich,. about S3~ In l~72 H,m'lett Packard came out sct~e m lq31. It has gone on to be a I~werful with the lqr-3q, tbe nemesis of the slide rule. tt~,l of diagm~sls and invt.'stigati~m in many Notes and References l'ht~, dt.'~psh" the fact that it cost at least an scientific awas. In the past ten years I have onh, r of magnitude more than a slide rule and P H~p, Sidle RuI~ their tt~torv.. It/k~k'ls. and Makers, bten ofiered two complete working electron ITS'9. had ~ hal many con,,,idewd, is the quirky micrt~copes. I had to decline as I had no Rex er~, i'oh~.h Notatatm These early calcula- customers who were prepared to take ~n an W MIer-JedrJe~,wicz, A Guide to HP Handheld Io~ are t'olh'ct,~.4 and traded, there are instrument that filled a small garage. Sadly, it Cah'ulefi*r~end Computers, 1996 coikx-tors club',, prk'e guidt~S, laity, and SI'~WeS must be as..,umed that t~solete models "are thrown away. Electnm microscopes have m~t T tladd~wk, A C,gM'h~r~ GN~¢ h~ Per~mmlCompute~ Aviation Instrumentation grown smaller as time pn~res,,~es. Although and I),~&rt Cah'ulahrrs, I~3. Manned nxt,d wmg flight ts los than 100 years the electn~nics has become n~we comp,wt, computers and other image analysis apparatus G. Balland B. Fhmm. The Comp/efeCoflect0cs Gua/¢ To old ln.,,trumt'nL,, of great x antqA" ~.ere necded, Pi~'/wf (Tdh'u/atcPr~,i"Jq7. m,m the beginning Of the centu~' sl~'ciallst have bern added, omtnbuting to the overall bulk. compa,,~es and altlmett,rs. to more complex RP Hdwt*, ']'he I|iMtWV ed the Avtwnettq", SiS Bulletin. Nit 37, pp Z~-27." g~,rt~.om~l~..-.es ar~| artificial honzon.~ There Global Positioning System art, large quantttws of th~,e item.,, a'~adable to be htund m n~nv ma-~,ct,, t[owever, the n~re [he (htghtred ~cietv. Dedicated to the H~my and This navigation sv~em that uses signals frcnn Collectkm tff Hide Rules, Secretary Wayne Lt.hnt~, mt~iern items Will bccome rarer as arms a series of satellites put paid to tbe manne PO I~ Vq(r77, Ermqyvilk,. CA ~2, USA hmitaflon tn,ahe~ require the d,.~.trucfi~n of >extant and chrt,nometer as a means of mthtarv hardware I suspect that th~.~e ~lth nav,gation. The advent of the powerful Autlwr'~ address: main mtt~t-',~t L.t the hlMorv off avhttl0ql rather computer chip enabled the pn~uctmn of P.O. &~x 4252 than that ,~ _~"wnhhc m..,truments them.q,h'es hand,~s that boat owners, hikers anti others OQY collect these m-.truma'nts /~,&m SW20 use to know their position of the surfag'e of the dgs~sc~enceont~qws.cam

Bulletin of the .~'wntitic Instrument ~riety No. 6,t (1999) Book Reviews

Opinions expressed by revieu~rs are their own, and do not necessarily reflect the vicu~ of the Editor or the Society

Everest The Man and the Mountain Readers of the Bulletin may be disap eses, the politics of the 17'h century pointed by the treatment of instruments Catholic Church, and Galileo's heresy. I.R. Smith in this btn)k. We are told that Everest had Whittles Publishing His book is not the first review of a mountain barometer, but not the type meridians, but is certainly the most Caithness, 1999 or maker, also that he had little interest in 306 pp., illustrated comprehensive. Italian cathedrals are levelling or in pendulum observations - generally the first to come to mind as ISBN1-870325-72-9 hence we learn nothing of these instru- Price £37.50 repositories of classical meridians, and ments. Smith has mistakenly attributed sure enough we are soon taken behind Mount Everest was conquered a genera- the prismatic compa~ to Kater; it was C. the scenes to witness the machinafi(nx~ tion ago, but no-one has hitherto A. Schmalcalder who patented in 1812 receding the instailati(ms of meridhms in attempted to encompass the life of Sir the prism which rapidly replaced the ~iorence, I~)logna and Rome. The sheer Ges)rge Everest (1790-1866), Surveyor- mirror which Kater had proposed in Ix)we and influence involved in forcing General of India. The mass of papers 1811. We read that the 3-ft theodolite of local religious communities to permit held in the Natkmal Archives of India 1830 was hand-divided by Edward digging-up floors and the knocking of and in the British Library's India Office Troughton, whereas William Simms has holes in the fabric of their jealously Records, from which the author quotes m dHafled his own work on this instrument guarded cathedrals is truly awesome! exten.q), expand on the contemporary in his 'Dividing Notebook' (Vickers This is why Heilbron can make what published accounts of the Survey, but Archive). Neither this source, nor Insley's imtially seems an astounding claim: that independent views of Everest's character succinct account of the Everest theodolite from the Middle Ages to the Age of and achievements appear to be sparse. (SIS Bull., No. 43, pp. 22-3) are referenced Enlightenment, the Roman Catholic here. Church probably gave more financial Surveys of India began before Everest's Anita McConnell and social support to the study of time, but he undertook the geodetic astronomy than any other institution! framework needed to support detailed The Sun in the Church: Cathedrals as An important part of the author's country surveys. His cumbersome yet Solar Observatories strength in analyzing these instruments delicate instruments had to be tran~ I.R. Heilbron and their results Ls that he is well able to ported the length and breadth of India, Harz~rd Uniz~rsity Press handle the mathematics invoh'ed, pro- as part of a huge animal-borne train of Cambridge, Mass. & London, 1999 viding a number of appendices on some lesser apparatus, a~istants, soldiery and ISBN 0-674-85433-0 of the trickier aspects. providers of food and shelter. Price £21.95 Only one deficiency is apparent in the While accounts of toil and privation The ecclesiastical year begins on Easter text - but a flaw common to many recent make a good read, explaining the Sunda,,; which the old theologians de- books on the history of science - namely mathematical complexity of such a creed should be celebrated on the first a virtual absence of references to fairly survey is less digestible, and Smith has Sunday after the first full moon following recent work published in ioumals not divided his book into essays on Ever~t's the vernal equinox. In principle therefore recognized as bek~nging to the corpus of life and work; The Park Estate and family one need only recognize the equinox, 'history of science. Does a trawl through matters; The measuring and naming of wait until the next full moon, and then Ph~ics Abstracts really produce nothing Mt Everest; and five appendixes: instru- declare the following Sunday to he Easter of relevance and value? It d(~s seem that mentation; instrument-makers; the atlas; Day. This procedure would give the right many modem historians of science want Everest as administrator; and the figure date - but not enough time to prepare it! to retreat to an insulated private enclave of the Earth and geodesy. Also, how does one recognize the where they can forget they are supposed equinox? So, in practice, there are two to be reporting (or at least taking account When it came to obtaining instruments of) the much larger world of ongoing Everest was handicapped by his distance requirements: one is to directly observe the date on which the vernal equinox science beyond a cut-off date of 1900. from London, which put him at the A.A. Mills mercy of his masters. He inherited a falls,the second is to evolve such a good chain and a zenith sector by Ramsden, a quantitative understanding of the appar- The Victorian Amateur Astronomer large theodolite by Cary, and other ent motions of the sun and mo(m that the Independent Astronomical Research in ob~)lescent apparatus, it was only when date of Easter can be reliably predicted Britain 1820-1920 many years in advance. he spent 1826-30 on sick leave in Allan Chapman England, that Everest was able to visit The scientific instrument that made Wilev-Praxis Series in Astronom~ and Colby's Irish Survey. Troughton & Simms possible the accurate solar observations Astr~)ph~ics made six sets of Colby bars, which ! essential to accomplish these aims was John Wil~ in Association with Praxis, believe (although not stated here) in- the meridian: in this context a long north- Chiciwster, etc., 199.8 cluded those for Everest, and we have a south line laid down upon a truly 256 pp, illustrated brief account in the first part of the book horizontal and stable fiat surface within ISBN 0-471-96257-0 about their testing at Lord's cricket a dark enclosure. A small hole in the roof, Price £40 ground. Everest aLso called on Troughton or high up on a south-facing wall, Practitioners of astnmomy, much as th(~e & Simms to discuss the construction of a projects an image of the solar di~ of any other activit',; can be divided into 3-ft theodolite and various smaller mod- crossing the line every, noon, at a point subcategories that depend largely upon els, among them the well-known 'Ever- along its length dependent on the time of the motives of those who do the dividing. est' theodolite. year. Ob~rvations over the years(s) Some subcategories, invoking such func- enable the equinoctial crossing point to Everest also convinced his masters of the tional distindions as 'astrophysics', 'solar be defined. Accuracy is a function of system astronomy', 'celestial mechanics', need for an instrument maker in India, dimensions so, very conveniently, med- permit pedagogical sorting, facilitate and recruited Henry Barrow, who arrived ieval cathedrals famous for theirsize and in India in 1830. Fortunately for us, if not administrative order and are rea.~nable holygloom lent thenxselvesbeautifully to descriptors - more preci~ than the much for them, as relations between Everest this theologically vital task. and Barrow soured, Everest penned broader, more inclusive 'astronomy'. lengthy and informative documentation Heilbron shows with wit and erudition Perhaps the most interesting distincti~m on Barrow and his working life. The how this apparently rather mundane separates a cohort that has been educated appendix on instrument makers deals endeavour impinged upon the wider (or trained) in a proscribed manner and only with Barrow and his successor issues of a stationary versus a moving uses that knowledge to obtain a liveli- Mo'hsin Hus~in. earth, Ptolomaic and Copernican hypoth- hood, from another cohort containing

Bulletin of the Scientific Instrument Society No. 63 (1999) 37 auh~tidact practiti(mers who view the The great galaxy of less well financed pancreatic ultrastructure, the astronom- sublect as Sl~rt, not livelih(ngl. This and educated amateurs are in many ical sportsman (person) often has little distinction between 'professional' and ways the most interesting and it is here regard for the theoretical or long-term 'amateur' while involving a livelihtx~d that Chapman's book brings them to the multidi~iplinary pri~ct: the goal is to test, is actually a far more complex i~ue forefront by treating them and their bag not an elephant, but M51 or split involving motive and product. activities seriously. Amateur asmmomy Epsilon Lvrae. One might thus wonder Chapman's Victorian Amateur Astronamer mirrors a general social trend of the al~ut Chapman's choice of a subtitle, is a complex work, dissecting the dem¢~'ratization of knowledge. Through- given the decidedly non 'research' as- phenomenon of amateur Astronomy out this work Chapman recognizes pects of the bulk of amateur astronomy. and following many of the actors, their another quali~' to this endeavor - the ,societies and their often complex relation- deep pets(real satisfaction felt by indivi- The amount of material contained in this ~ips to the subject of astronomy dunng duals who look at the sky through their well-written book is staggering, yet the period in which amateur astronomy, tele.~opes. The product of amateur questions remain. We catch glimpses of as it is generally known today, began. ¢~serving, especially as more individuals interaction with the Continent via such There are many paths that criss-crc~s and were recruited into the ranlc~, seemed to actors as Barth, but what of America with astronomical many subplots in the emergence of what, be this personal satisfaction. Chapman, its blos,~ming enterprises? while not a di~ipline in it~lf, is certainly in his delicious description of Webb's Much of the mirror and lens grinding a social and intellectual movement, often activities, and the intently personal, information in the English Mechanic was of great ~mportance to the astronomy relationship Webb had with the visible eagerly absorbed here and although practi:,~i by professionals. Chapman universe in relation to his own religious Chapman recognizes the contributions identifies: and follows skilfullv these faith, almost tempts us to evoke compar- of such workers as Clark, what about disparate paths and permits their mean- ison to mystical alchemical practice of Brashear? Did the si]ver-on-gla~ spec- derings to weave a wonderful tapestry of two centuries earlier. Certainly a glimpse ulum revolution spawned in Britain Volksz~'rsta, ndnis - with the warp and of M51 did not have a "scientific' mean- depend at all on his silvering process? w~n~f the people and their telescopes. ing for Webb, but such relationships to But to emphasize omissions would be to Some individuals, termed bv Chapman the cosmos stirred him so deeply and detract from this most germane work; the '(grand Amateurs', had tl~e education gave his I:n~ks on the subject of visual Chapman's b~n~k will certainly rai~ and the resources to undertake leading- astronomy a ring so brilliant they are questions and stimulate more enquiry. edge .scientific work, but numerically read today by amateur astronomers. And Which is another strength of this pioneer- they were in the minority. Their cimtribu- it is this personal reward as an end in ing effnrt. tions did however influence the direction itself, so clearly identified by Chapman, Francis 1. Mmmsek that professional astronomy t¢n,k, and that also characterizes many amateur Dartmouth Medical Schoal many of the names. Nasmyt'h, de la Rue, activities but also, perhaps, is the in- La.~,~l are as well known as those of their tellectual fifth column that limits the ~ rofessional contemFa~raries. Perhaps scientific utilization of the myriad ob- ere the biggest distinction was that they sen'ations made by these people. These Book Note did not derive their livelihta~d from their amateurs have evoh'ed their own sub- activities, whereas profes,~ionals did. culture that is in many ways distinct An English translation of Fons Vanden Much of the advance in telescope mak- from that of the mainstream astronomy Berghen's Classics of Communication, re- ing, particularly refk,cting telescopes, vet it is tht~e distinctly recognizable viewed in SIS Bulletin, No. 59 (1998), p. was amateur-driven and it was th~e of shared values that convey disciplinary 35, is now available from the author, independent means that were able to identity to amateur astronomy. Much as price £15 plus f,3p& p. He can be construct some of the leading-edge de- the afiimal trophy hunter cares little contacted on tel. +322 3560556 (after 8 signs of the period. about the elephant's physiokgy or i~ pro), or [email protected]

Current and Future Events

1 December 199q - 24 September 2000, phone/fax: +44 181 866 86~, mobile: 22 October 2000, London, England Greenwich, London, England 0-R)3 788 ~Y'/. lntemet: www.peterdele- har.co.uk. The Staru of Time exhibition m the 17'h- The 29th Scientific& Medical Instrument Fair will he held at the Radi~m SAS century Queen's House, part of the 2 - 7 May 2000, SiS Conference, Milan, Nation'al Maritime Mu~,um This is a Pavia and Lake Como, Italy Portman Hotel Portman Square, London truly international exhibition, bringing WI. Details as above. This year's annual visit is planned for 2 - tog~.ther around .'~1 ~khlects to print 8-14 July 2001, Mexico City, Mexico an all-encomrassing history of time 7 May 2iX)0. Plea~ consult the enclosed rt.'sponseflyer. acrL,ss the earth from the earliest civiliza- XX ScientificInstrument Symposium to be tions. 4 - 8 September 2000, Oxford, England held within the InternationalCongress of 16 April 2000, London, England XIX Scientific lustrument Stmll~siunz orga- the History of Science. nized by the Scientific Instrument Com- ]he 28th Scn'ntlh," & Medical Instrument mission of the International Union of the Summer 2002, Athens, Greece Fmr wdl be at the Radisson SAS Portman History. and Phik~phv of Science, ks to Hotel, Portman Square, London W1, be held at Oxflwd at tile Museum of the XXI Scient!~cInstrument Svmposium to be from I0:00 to 16:00 hours. Nearest held within the Internati(malCongress of History of Science, Broad Street, Oxflwd the History of Science. Underground station is Marble Arch. OX1 3AZ, UK. Consult the website at Lh'gantzer: I'eter [~'lehar, 146 l)ort~ello http://www.sic.iuhps.org for all SIC Details of future et~,nts, meetings, exhibi- Road, l.ondon Wil 2DZ, U.K. Tele- Symposia. tians etc. should be sent to the Editor.

38 Bulletin of the ~'wntlfic Instmn~,nt ."h~ciety. No. 63 0999) Classified

Scientific Instrument Society Summary of Advertising Services For further informatitm contact the ~)ciety's Executwe Officer (details on reside cover). Llthoflow Ltd act as agents for all advertisements but any sen'ices taken up will be treated as a c~mtract with the ~cietv. Page rates for camera ready artwork supplied: Whole page £210 Half page £110 Quarter page £60 Eighth page £42 Other: Additional artwork At cost Classified 25p per word (minimum charge £t;) U~ of box number £1,50 (apply to SIS Executive Officer) Flyer supplied by customer £15 Flyer supplied as camera ready copy • ./7,,~,/,~,,l,h, , .,/,,,t,9~ Single side £I 20 Two sides £1~ Special mallshots - as for flyers plus postage and handling charge 65 Ponohcllo Rc~J London W I I Tel~Fax: (IO.44.(0) 11,11.969.7011 There are no direct reducti~ms for placing adverti.,~nnents in more than one ~ue but page rates will qualify, for a 10% rtaoate tm each set of 4 con.,~,cutive identical advemsements. Final copy must be with Lithoflow Ltd no later than 4 weeks before publication of the Bulletin, \ o,.,,o.. w end January, April, July, Oct~g'~er All detailed arrangements to be made direct with Lithoflow Ltd. __1 Payment Invoict.'s will be is,sued by the ,~,.'iety immediately after publication of an issue of the Bulletin Terms 30 days after date of invoice. ~'he ~)cietv is not registered for VAT.

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SCIENCES • TECHNIQUES • MI~DECINE The Society has now published over 50 Bulletins, each packed with information about scientific instruments and happenings within the Society since its founding in 1983. The complete set make an invaluable Reference Library.

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Chairman's Address ...... 1 Editorial ...... 1 Cover Story...... Wdfem i-h,ckmmm 3 The b~run',ents of Appi~l Science ...... Robert Bud 3 The Van de Gr~f Generator. An F.lectros~tic Machine for the 20~ Centur~ ...... Paolo Bcmm/ 6 Ten 20" Century. Instruments at The Smithsonum m Wastungton, D.C ...... 14 Ten Important Twenueth-century Items from the History of Science Collections of the National Museums of Scotland ...... A.D. Momson-Low, R.H. NutUdi and A.D.C. Simpson 23 The Electron ~ered, 1897 - J.J. Thomson's Appanth ...... Alan Q. Morton 29 The Spinthanscope - The Instrument of William Crookes that Made Alpha Particles Vmble ...... H.C. Bolton and J. R. Patterson 31 Lord1 Radio Telescope at Jodrell Bank ...... Kevin Johnson 34 Market Place of 20~ Century lnsmunents ...... Desm(md Squm~ 35 Book Reviews ...... 37 Current and Future Events ...... 38

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