Written by Lightning A short story of lightning recorders: ceraunographs, electrographs, klydonographs Part 1 From Becaria’s Ceraunograph to Gergely Palatin’s Detector
Paolo Brenni
Foreword a lightning discharge was strong or close Since the mid-18th century atmospheric elec- enough to the ceraunograph a spark jumped tricity both in fair weather and during thun- between the gap of the conductors and perfo- derstorms was detected and measured with rated the paper disk. From the size of the hole a series of instruments such as spark gaps, it was possible to estimate the intensity of the electric chimes, electroscopes, electrometers lightning. From its position on the disk with and later galvanometers, which were gener- respect to the XII hour line, it was possible to ally connected with an aerial.1 Lightning re- determine the time of the discharge. Further- cording devices were mainly developed in the more, according to Beccaria, if the position of framework of wireless technology, between the hole corresponded to the upper electrode the very end of the 19th n frst ye rs of the (1), the lightning occurred downward from the 20th century, but their origins go back to the clouds to the earth. On the other hand, a hole ceraunographs proposed in the 1780s. In this aligned with the lower grounded electrode (2) article in two parts I will retrace the history of indicated an upward discharge from the earth 5 the instruments which allowed to register di- to the clouds. However, the ceraunograph rectly (on er resin hoto r hic flm etc.) was a very imperfect instrument. The sparks lightning strikes or sudden variations of atmo- produced by two or more lightning events in s heric electricity fel urin thun erstorm. rapid succession proceeded to pass throughout a single hole instead of perforating the paper Beccaria’s Ceraunograph and its several times.6 Furthermore, sometimes the Modifcations spark did not perforate the disk in correspon- Giovanni Battista Beccaria (1716–1781), the dence with one of the electrodes, but some- renowned Italian “electrician” taught phys- where between them. ics in rious It li n cities n fn lly occu- Becc ri s not s tisfe ith this frst pied the chair of experimental physics at the apparatus and in the same paper he proposed University of Turin. He was an excellent ex- a second improved version. There is no origi- erimenter n his rese rches in the fel of nal illustration of it, but from the description electricity (in which he supported Franklin’s Fig. 1 The original ceraunograph described I could draw an ideal reconstruction. (Fig. sin le ui theory) ere mon the most re- by Beccaria. The top image shows the disk 2) The instruments consisted of four parallel markable of his time. In 1780, Beccaria de- inserted on the clockwork mechanism. P and and horizontal cylinders, which could rotate scri e the frst li htnin recor in r tus S are the electrodes connected respectively easily. Two of them were placed higher than 2 and also invented its name – ceraunograph. with the lightning rod and with the ground. the other. A paper roll was wrapped on the The term derives from the Greek words In the other images the instrument in its box frst cylin er. he er t e sse et een 3 (thun er olt) n (to rite). with the horary dial. (Beccaria 1780, op. cit. the two electrodes (1 and 2) over the pair of note 2). Becc ri s frst cer uno r h s com ose higher cylinders and was rewound of a clockwork mechanism with a vertical axle on the last one. This was connected (Fig. 1). A horizontal recording paper disk was with a rope to the driving weight of inserted on it. The disk was supported by a a pendulum clock. The descent of series of radial straws inserted in the axle. A the weight moved the cylinder and t circul r o ith circul r o enin ro- rewound the tape. Finally, a counter- tected the clockwork. The rim of the opening ei ht on the frst cylin er e t the carried a horary annular-shaped scale divided tape in tension. With a long tape, on in 12 hours and minutes. A radial line had to which there was a horary scale for be marked on the recording disk in correspon- many days, it was possible to have a dence of the XII (midday or midnight), so long recording with several thunder- that it was possible to have a time reference. storms registered. By using a clock The pointed lower end of an aerial conductor4 with a long and relatively fast move- (electrode 1) terminated near the upper face of ment of the descending weight, the the paper disk, while the upper end of a second risk of having a single hole for more wire (electrode 2), which was grounded, end- than one spark was reduced. ed near the lower face of the disk. The termi- Unfortunately due to his poor health, nals of the two electrodes were aligned along Beccaria could not experiment with a same radius of the disk, but their distances Fig. 2 A modern illustration reconstructing the second version of Beccaria’s ceraunograph. from the centre were slightly different. The electric discharges were recorded on a long roll of paper passing between the two During a thunderstorm, lightning induced electrodes. The inscribed paper was rolled around a cylinder moved by the falling weight of a voltage surges in the aerial conductor. If pendulum clock. (Diagram of the author).
2 Bulletin of the Scientifc Instrument Society No. 145 (2020) Fig. 4 The very complicated meteorograph proposed by Vassalli-Eandi. The recording anemometer and a recording wind vane with their recording drum are on the left; the barograph and the thermograph together with a clock are placed in the centre, while on the right there is the ceraunograph. The latter was actioned by a glass rod connected with the clockwork of the Fig. 3 Cavalli’s cronio-ceraunometer. The croniometer recorded anemograph. (Vassalli-Eandi. 1803-4, op. cit. note 12). the hour and then quantity of rain on the internal ring of the clockwork driven disk. The quadrangular funnel collected the rain which flled the small vessel fxed on the lever with a pen. and marked a trace on Electric discharges were recorded with the ceraunograph on it.10 When the rain ceased the external part of the disk. The bar connected to the lightning the vessel was completely rod and the one going to the ground are equipped with quadrant emptied by a special sy- electrometers. (Cavalli, 1785, op. cit. note 8). phon and the action of the spring raised the lever. this second ceraunograph. But an almost iden- With Landriani’s apparatus it was possible to tical instrument was made following Becca- record the hours of rain and because the wa- ria’s suggestion by Francesco Giuseppe Gar- ter coming from the vessel was collected in a dini (1740–1816) a physician and natural phi- graduated cylinder so that it was also possible losopher, who had been a disciple of Beccaria to measure the quantity of fallen rain. Cavalli himself.7 Gardini described his ceraunograph rofte from the f ct th t oth the chroniom- in 1785 and extensively used it in his studies eter and the ceraunograph were equipped with on the in uence of electricity on l nts. a rotating recording disk. With the chronio-ce- In the same year, the Roman abbot and astron- raunograph it was possible to record one near omer Atanasio Cavalli (1729–1797) described the other and on the same disk the hours of rain a new instrument which he baptised with the as well as the time of the electric discharges. name of cronio-ceraunometer8 (Fig. 3). This By comparing the two traces one could at- s the com in tion of the frst Becc ri s ce- tempt to establish some relationship between Fig. 5 The detail of the ceraunograph raunograph with a recording rain gauge, which the two meteorological phenomena. The in- illustrated in the previous image. The had been invented by the Italian chemist, strument was installed in the Roman private electrode connected with the lightning physicist and meteorologist Marsilio Landri- observatory known as Specola Caetani.11 rod ended near the upper face of the disk. ani (1751–1815). In Landriani’s Chroniho- It was also connected with a gold leaves Around 1800 the Italian physicist and math- metro9 the rain was collected by a funnel and electroscope, which detected the atmospheric ematician Antonio Vassalli Eandi (1761– throu h i e th t flle sm ll essel l ce electricity when this was too weak for 1825) proposed a complex meteorograph.12 at one of the extremities of a lever connected producing a spark across the disk. (Vassalli- The apparatus included an anemograph and to a spring. A pencil was inserted vertically in Eandi. 1803-4, op. cit. note 12). a wind vane, a barograph, a thermograph the same lever and under it there was a rotat- and a Beccaria’s ceraunograph13 (Fig. 4). ing disk with a horary scale mounted on the The disk of the ceraunograph rotated thanks transmitted to the disk via a connecting glass axle of a clockwork mechanism. During the to the clockwork moving the recording drum shaft and some gears (Fig. 5). But this mete- hours of rain the weight of the vessel (which of the anemograph. The ceraunograph was orograph was probably never constructed. In remained full of water) lowered the lever and located in a separate electric pavilion and the 1780s the Italian physician Pietro Moscati thus the pencil was in contact with the disk therefore the movement of the clockwork was (1 1 24) ho s intereste in the in u-
Bulletin of the Scientifc Instrument Society No. 145 (2020) 3 spite of the fact that ceraunographs were also mentione in forei n scientifc liter ture15, it does not seem that these instruments were common outside Italy. Lichtenberg’s Figures and Ronalds’s Electrograph In 1777, the German physicist and satirist Georg Christian Lichtenberg (1742–1799) isco ere the f mous f ures n me fter him.16 The two-dimensional Lichtenberg f ures re ro uce hen o er (ch l red lead, sulphur, etc.) is sprinkled on electric charged dielectric plate (resins, hard rubber, l ss etc.). he f ures re ifferent e en - ing of the charge of the plate. Generally posi- ti e f ures sho l r er r orescent tterns while negative ones are smaller and have a sharp circular or globular boundary almost en- tirely devoid of branches. Lichtenberg made many experiments. In one of them, he traced some lines on a resin plate with the top of the internal electrode of a charged Leiden jar. The lines (drawing or writings) clearly appeared when the resin was sprinkled with powder (Fig. 6). In 1778, Lichtenberg also proposed (but probably never realised) a device for re- cording important variations of atmospheric electricity with a clockwork-driven tin drum which was covered with a layer of resin. An electro e connecte ith ite s f e perpendicular to the drum and its pointed end was placed near to the surface. After a complete revolution of the drum, some elec- troscopic powder was sprinkled on the resin and a registration of the variations of the elec- trical state of the air appeared.17 In fact, the electrical discharges induced in the antenna connected to the kite charged different areas of the resin which produced various Lichten- er f ures. Simil r e eriments ere lso made by the English clergyman and physicist Abraham Bennet (1749–1799). He devised a special electric pen (in fact a very thin Leiden jar, which was repeatedly charged by touching a larger jar) and with it he traced drawings on a resin cake. He also used a simple apparatus which allowed him to draw spirals, circles and volutes with his pen.18 Bennet also mentioned an instrument imagined by Landriani for re- cording atmospheric electricity on a rotating resin plate.19 But in spite of many ideas which remain only on er ro ly the frst function l recor - in r tus usin ichten er s f ures s Fig. 6 Some of Lichtenberg’s experiments. Images F.7 and F.8 show how to write on a resin described in 1823 by the English scientist and plate with a charged electrode (Lichtenberg, 1778, op. cit. note 16). inventor Francis Ronalds (1788–1873), who was one of the pioneers of electric telegra- phy and who made extensive studies on atmo- ence of the environmental and meteorological an ‘elettrografo’, which was an improved and spheric electricity. Around 1813, Ronalds was conditions on human health and hygiene, in- more so histic te ersion of the frst cer u- informed by his friend the pioneer electrician stalled in Milan a well-equipped meteorologi- nograph described by Beccaria14 (Fig. 6). George Singer (1786–1817) of Landriani’s re- cal observatory with a series of sophisticated By the end of the century various apparatus of cording apparatus.20 on l frst im ine recording apparatus. Among them there was this kind were installed in Italy. However, in kind of recording instrument (essentially for
4 Bulletin of the Scientifc Instrument Society No. 145 (2020) ning strikes were proposed. But in the second half of the 19th century a series of discoveries and inventions opened the way for a new generation of thunderstorm detectors and recorders. In the 1860s, the Scottish mathematical physicist James Clerk ell (1 1 1 ) e elo e his unife theory of electromagnetic radiation which brought together electricity, magnetism and light as different manifestations of the same phenomenon. Maxwell’s four equations de- scribe the behaviour of electric and magnetic fel s n ho they re ener te y ch r es and currents. An important consequence of the e u tions is th t they sho ho uctu t- in electric n m netic fel s ro te s electromagnetic waves. Their existence was demonstrated experimentally by the German Fig. 7 The frst Ronalds electrographs. The Fig. 8 The second simplifed version of physicist Heinrich Hertz (1857–1894) in the resin did not move, while the arm supporting Ronalds electrograph. The resin covered disk 1880s. In 1890 the French physicist Édouard the wire with the beads rotated on the resin was inserted on the arbour of the clockwork Branly (1844–1940) invented the so called disk. (Ronalds, 1823, op. cit. note 21). and rotated. The moveable arm was ‘radio-conducteur’: an insulating tube (ebo- connected with a lightning rod. (Ronalds, nite, glass, etc.) containing some metallic 1845, op. cit. note 24). flin et een t o electro es.26 Branly dis- studying fair weather electricity) with a series co ere th t the electric resist nce of the fl- of very well insulated electrometers. They electrically charged the plate along the spiral ings, which was normally in the order of 106 were charged one after another by a moveable path following the changes of the atmospheric ohm, could suddenly decrease to 103 or even 22 electrode connected to the aerial conductor fel . This apparatus allowed one also to reg- 102 ohm and became a conductor when in the so that each of them could give the electrical ister the voltage surges induced in the aerial presence of electromagnetic oscillations. He state of the atmosphere at different times dur- conductors by lightning strikes. Finally af- also observed that the high resistance state ing a period of a day or more in the absence ter several hours the plate was removed and of the device could be re-established by sim- of an observer. Around 1814–15 Ronald con- sprinkled with powder (Ronald suggested the ply tapping on the tube. A spark discharge of sidered using a disk of resin for recording the use of common dry hair powder!). A spiral a Leyden jar or of an electric machine, were variation of atmospheric electricity and pro- ith n rr y of ichte er s f ure e re enough to drastically change the resistance posed his electrograph, which in fact was the and the variations of their form and breadth of the coherer. According to the common ex- frst r tus of this in hich s c refully corresponded to the changes of the electrical planation at the time, when electromagnetic designed and constructed. This apparatus also state of the air. waves were set up in the neighbourhood of allowed one to register the electric discharges In the 1 40s on l s mo ife n sim life the device, electromotive forces were gener- induced in the aerial conductors by lightning his electrograph (Fig. 8). In the new version, a te in it hich e re to fuse the flin s stri es. on l s frst escri tion of the elec- plate with a thin coat of resin rotated while the together, that is, to cohere the particles, and trograph appeared only in 182321 (Fig. 7). A 27 electrode connected with the antenna moved thus their electrical resistance decreased. box contained a weight-driven clockwork on it like the tone arm of a modern record The term coherer, which became commonly mechanism. On the box there was a circular player. This instrument was adopted in the used, was introduced by the British physicist wooden plate with a hole in its centre and a 1843–44 in the Kew Observatory23 and later and inventor Sir Oliver Lodge (1878–1955). time scale divided into hours and minutes on also in the Greenwich Observatory until at Lodge, who in the 1880s made several re- its periphery. A removable disk of resin with least 1846.24 on l s ne er ery s tisfe searches on lightning, lighting rods, electrical a hole was placed on the plate. A glass tube with the electrograph because of problems in sparks, and oscillatory discharges of Leyden covered with a cap was inserted into the for- making the resin coating, which had to be per- jars, was one of the pioneers of wireless trans- mer and protected a glass stem connected to fectly compact, homogeneous and of uniform mission. In his experiments and demonstra- the clockwork. The stem had a metallic cup at thickness. In Kew a calotype image of a Lich- tions with Hertzian waves he used improved its upper end with a thin horizontal steel rod. ten er s ir l sh e f ure s successfully Branly’s coherers. Lodge (and others) had On it there was a fork-shaped slider which t en ut fn lly on l s n one the e- also observed that the coherer also responded supported a vertical wire. A small gold bead 28 vice and focussed his attention on developing to atmospheric discharges. Following his re- touching the resin was hanging from a wire new photographic recording instruments such search, he also believed that lightning, like for ith hoo . fne thre s tt che to the as the photo-electrograph.25 example the sparks of Leiden jars, were oscil- slider and to the top of the cap of the glass latory discharges producing damped electro- tube. When the clockwork was working the Going Wireless magnetic waves. This erroneous belief was glass stem and the rod rotated with the verti- After the 1850s, Beccaria’s ceraunographs the commonly accepted until the beginning cal wire and at the same time the thread was were forgotten and Ronalds’s electrographs of the 20th century. Today we know that light- wrapped on the cup of the glass tube. In such were abandoned. The study of fair weather ning events are rapidly pulsating unidirec- a way the gold bead traced a spiral on the atmospheric electricity continued in many tional discharges, however for this discussion resin cake. The cup contained some mercury observatories and with improved recording it is enough to know that their radio frequency and the wire connected with an antenna or a instruments, but for almost half a century no electrom netic fel s ct on the resist nce of lightning rod was dipped in it. So the bead ne s ecifc instruments for re isterin li ht- coherers. Furthermore since the 1890s, with
Bulletin of the Scientifc Instrument Society No. 145 (2020) 5 Fig. 9 (and Cover) Lightning detector of Alexander Stepanovich Popov. the rapid development of wireless technol- ogy other types of radio wave detectors were developed.29 The invention of the coherer Fig. 10 Original scheme of Popov’s lightning detector. The same kind opened the way to the wireless transmission of circuit was used by several devices of the same type and by the early of signals, and to a completely new system of wireless receivers. (Popov, 1896, op. cit. note 30). detecting and recording lightning discharges. Popov Lightning Recorder The Russian physicist Alexander Stepanovich bell for tapping the coherer was an original in- if his recei in r tus s in uence y Popov (1859–1906)(the name is sometime vention of Popov.) Two choke coils in the co- lightning.34 He observed that his device was spelled Popoff) is today remembered as one herer’s leads prevented the radio signal across detecting also very far electrical discharges as of the most important pioneers of wireless the coherer from short circuiting by passing well as very faint heat lightning. Boggio-Lera communication. Popov was particularly in- through the DC circuit. This basic circuit considered that it would have been useful to terested in electrical technology and in 1883 was reproduced with some variation in most add a recorder to the detector. Then, with the became instructor and chief of laboratory in lighting recorders proposed in the following support of the Director of the School of viti- the Navy’s Torpedo School at Kronstadt. Here years. In July of 1895 an improved detector culture, in July 1899 he was able to install his he became familiar with the works of Hertz, with the addition of an electromagnetic pen apparatus in the observatory of the Institute. Lodge and Branly, and after having improved with a Richard frères31 recording drum, was is frst recor er inclu e met llic o er the metallic powder coherer, in 1895 he built installed on the roof of the Institute of Forest- coherer (whose terminals were connected to an apparatus which could detect electrical os- ry of St. Petersburg. The apparatus was tested an antenna and to the ground), lightning ar- cillations produced by the discharges of elec- during the summer with the collaboration of rester, a Leclanché cell, a Hipp relay, 3 Ra- trical machines, and induction coils, as well G.A. Luboslavsky and several lighting strikes diguet cells and an electric hammer for tap- by the sparks generated by opening or clos- were recorded. In 1895–96 Popov’s attention ping the coherer (Fig. 11). The signals gener- ing an electric circuit including an electro- was attracted by the new rays discovered by ated by lightning strikes were recorded on the magnet, a capacitor or an inductance. But his Röntgen, as he continued to improve his de- er f e on the cloc or ri en cylin er apparatus, which was described in 1896, also tectors and recorders. In fact one of them was (2 revolutions in 24 hours) of a common Rich- recorded ‘the action of electric atmospheric installed in 1896 at the annual fair of Nizhny ard’s meteorological recording apparatus. A disturbances’ when it was connected with an Novgorod and when Popov read about Mar- simple mechanical contrivance slowly moved 30 antenna or a lightning conductor. (Fig. 9 and coni’s experiments and suddenly resumed his the recording pen in the vertical direction so Cover). experiments with wireless transmission. But that the trace of the latter appeared as a spiral In Popov’s original detector one of the termi- his further researches go beyond the frame of with a spire every 12 hour. The electric cir- 32 nals of the coherer was connected to an anten- this article. Popov’s device certainly was the cuit of the recorder was not really different na and the other was grounded. (Fig. 10) But frst ireless r tus for re isterin li ht- from other similar apparatus, but Boggio-Lera 33 it was also part of a circuit with a battery and a ning strikes. In the next few years several mo ife it y in secon rel y n elec- relay. The latter could operate an electric bell. inventors, physicists, electrical engineers pro- tric cell and by slightly modifying the electric Thanks to the radio noise generated by a light- posed a series of similar lightning recorders. circuit in order to distinguish between far and near lightning (Fig. 12). In fact by properly ning strike the resistance of the coherer sud- Boggio Lera’s Lightning Recorder denly dropped so that the current of the battery regulating the tension of the spring of the re- In 1898 the Italian physicist and mathemati- could switch on the relay and operate the elec- lays (and thus their sensitivity) and the one of cian Enrico Boggio Lera (1862–1956), who tric bell. But the bell hammer hit the coherer the hammer, he could record in a different way was professor at the Royal Technical Institute and restored its original high resistance state, the feeble effect of a far thunderstorm and the of Catania and at the Royal School of viticul- so that the detector was ready to receive a new stron er one of loc l storm. he frst ones ture and oenology, after having repeated some signal. (The reset contrivance using the alarm were marked with a ½ millimetre trace on the of rconi s frst e eriments eci e to test recording drum, the latter with a 2 mm one.
6 Bulletin of the Scientifc Instrument Society No. 145 (2020) Fig. 11 This Boggio-Lera lightning detector (without recording Fig. 12 This scheme illustrates the Boggio-Lera lightning recorder with device) was installed in the Royal School of viticulture and two relays (R and R’). With it one could register in a different way the faint oenology of Catania. From left to right: lightning protector, and far lightning and the stronger one of a local storm. (Boggio-Lera, metallic powder coherer, electric de-cohering hammer and Hipp’s 1900, op. cit. note 34). relay. (Boggio-Lera, 1901, op. cit. note 34).
Boggio-Lera also proposed a three-relay ap- violent thunderstorm started where the labora- paratus in order to differentiate local, far and tory was located.38 Tommasina hoped that his very far lightning strikes. But it is not certain simple instrument could have been useful on that such an instrument was constructed. Fi- board of ships for detecting and understanding nally in 1902 he wrote a new article relating a the trajectory of thunderstorms. series of mo ifc tions of the etector n of the coherer in order to increase the sensitivity Schreiber and Fényi Gewitter- of the apparatus and to avoid that of electrical Registrator oscillations disturbing the action of the relays. Lightning recorders seemed to be quite popu- In fact, he was looking for a better solution lar in the Austro-Hungarian Empire and vari- than the inductances, which were often used ous types were proposed by Hungarian scien- s flter in these in of etectors.35 tists and inventors.39 Tommasina’s Electro-radiophone During the year 1900, Johann Schreiber In 1899 Thomas Tommasina (1855–1935), a (1843–1903), who was assistant of the Jesuit Swiss artist who turned into a physicist, dis- astronomer Gyula Fényj (1847-1927) director covered that with a certain type of carbon of the Haynald Observatory in Kalocsa, con- powder it was possible to construct a special ceived a rudimentary thunderstorm recorder ‘auto de-cohering coherer’.36 The powder was (Gewitter-Registrator). After various trials inserted in the hole of a small ebonite plate n mo ifc tions the efniti e instrument between two mica plates. Two wires assured was ready in the Autumn, but it was neces- the connection with the carbon. The device sary to wait until Spring of next year to test had a remarkable propriety. The resistance of it. The apparatus was quite different from the powder suddenly dropped under the ac- Popov’s one, and was described in great de- tail by Fenyi, who greatly contributed to im- tion of an electromagnetic disturbance, but 40 immediately after that, the coherer became proving it (Fig. 14 ). Schreiber did not use de-coherised and the resistance returned to a metallic powder coherer but an imperfect contact coherer composed by two perpendicu- its original high value without any mechani- .41 cal action. In 1900 Tommasina, who knew the lar steel needles one laid upon the other The work of Boggio Lera, proposed a lighting de- nee les ere f e on the o of the electric tector called ‘electro-radiophone’37 (Fig. 13). bell which acted as acoustic alarm as well as The very simple apparatus was composed of a de-cohering apparatus. Instead of a telegraph- ic relay, Schreiber employed a moving needle telephone receiver containing a small carbon Fig. 13 This scheme illustrate Tommasina’s galvanometer. When, under the action of an coherer sealed in a glass tube. The coherer was electro-radiophone with the ‘auto de- atmospheric discharge the coherer became inserted in series in the circuit including a bat- cohering coherer’. (Tommasina, 1901, op. conductive, the current of a battery energised tery and the telephonic electromagnet. Finally cit. note 37). the terminals of the electromagnets were con- the coil of the galvanometer. Its magnetic nected with a grounding wire and an antenna ing the crackling sounds changed and became needle deviated and one of its pointed ends made of three 30 metres long wires. With the more intense. For example, on the 29th of Sep- touched a contact and closed a second circuit. electro-radiophone Tommasina could clearly tember 1899, with fair weather the electro-ra- This included a second battery, an electric bell hear the various sounds produced by far-off diophone produced various noises indicating a and an electromagnet operating the pen. The lightning. When a thunderstorm was approach- far-off storm. These increased in intensity and bell not only acted as a warning signal but its frequency until, after three and half hours, a vibrations de-cohered the two needles. The
Bulletin of the Scientifc Instrument Society No. 145 (2020) 7 Fig. 16 One of the disk recorded in 1902 with Palatin’s lightning recorder. (Tibor Horvát, 2001, op. cit. note 39).
vanometer coil, the resistance of the electro- magnets, and the length of the antenna, which had to be carefully chosen in order to obtain the highest sensitivity and the best recorded traces. It seems that around 1903 he was using three slightly different recorders. The large amount of data collected in Kalocsa with the lighting recorders seemed to be in Fig. 14 Diagram illustrating the Schreiber and Fényi Gewitter-Registrator. The couple of agreement with the observational data previ- crossed needles acting as coherer was on the box of the electric bell. The galvanometer was ously collected in Hungary. At the beginning used instead of a telegraphic relay. (Tibor Horvát, 2001, op. cit. note 39). of the 20th century, an improved Schreriber- Fenyi recorder was manufactured by the frm ohl of hemnit n sol for 1 0 signals were recorded by the pen on a vertical coherer was the fact that when the current was marks43 (Fig. 15). This type of recorder was paper disk which was inserted on the arbour too strong the needles stuck together. Initially, installed in several observatories both in Hun- of a clockwork so that every hour it made a he used a Meidinger cell (1 volt) with a kind gary as well throughout the rest of the world complete revolution. A simple contrivance of shunt in order to reduce the voltage at the (Pola, Manila, Lisbon, Nürnberg, Potsdam, slowly moved the writing mechanism from coherer to 0.25 volt circa. But in 1902 Fenyi Kremsmünster, etc.). At least two of them the periphery to the centre of the disk so that tried a new type of aluminium-zinc battery went to Africa: one in Johannesburg and the the recordings of a day were not superimposed (0.28 volt). He then experimented with several other in Salisbury (today Harare the capital on a single circle, but drew a spiral. needles-coherers connected in series (4 to 6) of Zimbawe). A Schreiber-Fényi apparatus is and could use a Meidinger or a Lechanché cell In the frst ye rs of the 20th century, Fenyi today preserved in the Museum of the Krems- without a shunt. It seems that he also made mo ife sim life n im ro e the - münster observatory.44 This recorder was experiments with metallic powder coherers. ratus.42 One of the problems with the needle made in Budapest by the clockmaker and me- He also improved the dimensions of the gal- chanic Victor Hose (1872-1957), who manu- factured a number of these apparatus. Gergely Palatin Detector In 1901, another Hungarian physicist Gargely Palatin (1851–1927), who was teaching at the Benedictine college of the Pannonahalma Ab- bey, became interested in Marconi’s experi- ments and conceived another lightning detec- tor.45 His coherer was neither one with metal- lic powder nor a crossed needles version. Pal- atin used a magnetic steel knitting needle cut in t o sections. hese ere li ne n f e horizontally leaving a narrow gap between their cent en s. Some iron flin ere sprinkled on the gap and because of the steel magnetisation formed a kind of bridge. The apparatus included the usual telegraphic relay Fig. 15 The improved version of the Schreiber recording apparatus by the German with an electric bell (acting also as tapper on manufacturer Max Kohl. On the left the detector, on the right the recording apparatus. (Max the coherer) two batteries, and (unusually) a Kohl, 1905, op. cit. note 43). galvanometer (simply used as an indicator).
8 Bulletin of the Scientifc Instrument Society No. 145 (2020) 8. Atanasio Cavalli, ‘Lettera II Del Cronio- metro del Sig. Cavaliere Landriani e del Ca- raunografo del fu P. Beccaria’ and ‘Lettera III Del cronio-ceraunometro, dell’elettroforo del saggiatore e dell’atmimetro’, Lettere meteoro- logiche romane. Tomo primo ( Roma, 1785), pp. 31-42 and 43-66. 9. Marsilio Landriani, ‘Descrizione del Chronhyometro ossia di una nuova macchina meteorologica’, Opuscoli fsico-matematici (Milano, 1781), pp. 21-49. 10. By radially shifting the pencil every day it was possible to have the same disk with re- cords of an entire week. 11. Mario Baratta, ‘La specola astronomica e meteorologica Caetani’, La Vita Italiana, Fa- scicolo 24 (1897), pp. 915-924. 12. Antonio Vassalli Eandi, ‘Notice d’un mé- téorographe’, Mémoires de l’Académie des Fig. 17 An old photograph of the lightning recorder in use at the Sciences littérature et beaux-arts de Turin, Gothard Observatorium. On the top of the instrument a Richard Sciences Physiques et Mathématiques, 1re par- recorder. The instrument (without the recorder) is still preserved today. tie, an XII (1803-4), pp. 426-444. (See: http://www.gothard.hu/gttak/archive-photos/categories/physmisc/ physmisc.php). 13. Vassalli Eandi also contemplated the pos- sibility of using a Beccaria ceraunograph of the second type. In 1902 the detector was also equipped with in giurisprudenza gli appresenta la descrizio- a recording device. An electromagnetic driven ne di un suo nuovo ordigno disegnatore de’ 14. Pietro Moscati, ‘Descrizione dell’Osser- pen inscribed the signals on a rotating disk fulmini (Torino, 1780) and Giovanni Battista torio meteorolo ico eretto l fne ell nno connected with a clockwork mechanism. The Beccaria, Di un ceraunografo e della ragio- 1780’, Memorie di matematica e fsica della disk made a complete revolution in one hour ne de’ tremouti (Torino, 1780). See also Fe- società Italiana, Tomo V (1790), pp. 365- while the pen slowly moved radially in order lice Garelli, Sulle dottrine elettriche nel sec- 381 and Edoardo Proverbio, ‘Sul Gabinetto to write a spiral. Up to 1907 Palatin made sev- olo XVIII (Mondovì, 1866), pp. 460-470 and meteorologico e sulla Specola meteorologica eral observations and today 90 recorded disks Michael Brain Schiffer, Draw the Lightning e astronomica di Pietro Moscati in Milano’, survive in Pannonahalma46 (Fig. 16). Down Benjamin Franklin and Electrical Tech- Memorie della Società Astronomia Italiana, nology in the Age of Enlightenment (Berkeley, 68 (1997), pp. 543-572. Finally, we can mention that in Hungary the London, 2006), pp. 179-180. engineer, instrument maker and astronomer 15. See for example Pierre Bertholon, De Jenö Gothard (1857–1909) and his collabora- 3. Late 19th century different type of cerau- l’électricité des météores, Tome II (Paris, tors also made a lightning detector of the Bog- nographs were also called thunderstorm- 1787), p. 306. gio-Lera’s type. Jenö and his brothers Sándor recorders, lightning-recorders, electrographs, 16. Geoorg Christoph Lichtenberg, ‘De Nova and István (1869-1848) founded the Herény brontometers, brontographs, ceraunometers Methodo Naturam ac Motum Fluidi Electrici Astrophysical Observatory near Szombathely. or electroradiographs. See Charles F. Talman, Investigandi Commentatio prior’, Novi com- Their main interest was astronomy, but they ‘The language of meteorology’, The Popular mentarii Societatis Regiae Scientiarum Got- also regularly made meteorological observa- Science Monthly, March 1913, pp. 272-279. tingensis ad a. 1778 (1778), pp. 168-180. tions. Gothard’s recorder is today preserved in 4.Beccaria mentioned the conductor, which the Museum of the Gothard Observatory now 17. Georg Christoph Lichtenberg, ‘Commen- was a kind of lightning rod, as flo esploratore part of the Loránd Eötvös University47 (Fig. tatio posterior super Nova Methodo Natu- della celeste elettricità (‘wire for exploring 17). ram ac Motum Fluidi Electrici Investigandi’, the electricity of the sky’). Commentationes Societatis Regiae Scientia- Notes and References 5. Beccaria also noted that the number and the rum Gottingensis per annum 1778, 1 (1779), 1. For an introduction to the history of these sizes of the holes also depended on the length, pp.65-79, (the apparatus is described at the pp. instruments see: Paolo Brenni, ‘ Prometheus’ the insulation and the position of the lighting 72-73). Tools, Instrument and Apparatus Used in At- rod. 18. Abraham Bennet, New Experiments on mospheric Electricity Research and Experi- Electricity (Derby, 1789), pp. 45-55. ments’, in Peter Heering , Oliver Hochadel, 6. For obviating this problem, Beccaria pro- David Rhees Jr, eds, Playing with Fire His- posed to cover the disk with a layer of cin- 19. Ibid. pp. 49-50. It is curious that no refer- tories of the Lightning Rod (Philadelphia: nabar (mercury sulphide). Two sparks pass- ence of Landriani mentions such an electricity American Philosophical Society, 2009: Trans- ing through the same hole would react with recorder. It is possible that Bennet confused it actions of the American Philosophical Soci- the cinnabar and leave on it two different and with the recording rain gauge or with another ety, Vol 99, part 5, pp. 230-255. separated traces. apparatus not by Landriani. 2. Giovanni Battista Beccaria, Giambattista 7. Francesco Giuseppe Gardini, De Infuxu 20. George John Singer, Elements of Electric- Beccaria delle Scuole Pie congratulandosi col Electricitati Atmosphaericae in Vegetantia ity and Electro-Chemistry (London, 1814). signor conte Prospero Balbo della sua laurea Augustae Taurinorum, 1784), pp. 28-31. Singer gave lectures on electricity and among
Bulletin of the Scientifc Instrument Society No. 145 (2020) 9 his audience were Faraday and Ronalds. Did metallic powder during a thunderstorm had body’s Magazine, 5 (October 1901), pp. 443- Singer repeat the dubious mention of Landri- been noticed since the mid-1850s by the tele- 447. ani made by Bennet? (see note 19). graph engineer Cromwell Fleetwood Varley 38. Tommasina made several observations (1828–1883). 21. Francis Ronalds, Descriptions of an Elec- both in his laboratory in Geneva as well as in trical Telegraph and of Some Electrical Ap- 29. Vivian J. Phillips, Early radio wave detec- his house in Intra on the Lake Maggiore. paratus (London, 1823), pp. 47-52. The in- tors (London, 1980). 39. In 2001 the Hungarian Electrotechnical strument was described several years later in 30. The original article appeared in Russian Museum in Budapest held an exhibition on The Encyclopedia Britannica (eighth edition), in the Journal of the Russian Physical and historical lightning detectors. The booklet ac- Vol. VII, 1855, p. 626 and in Tal. Schaffner, Chemical in January,1896. A complete Eng- companying the exhibition gives much infor- The Telegraph Manual (New York), 1867, pp. lish translation appeared only in 1900: Alex- mation about these kind of apparatus invented 153-156. ander Popoff, ‘Apparatus for the detection and used in Hungary. Tibor Horvát, 100 Éves 22. The velocity of the bead on the resin could and registration of electrical vibrations’; The Villámjelzők (100 years old Lightning Detec- be varied by connecting the moving system to Electrical Review, 47, 23 November 1900, pp. tors), (Budapest, 2001); see also Tibor Horvát, the hour arbour or the minutes one. Normally 845-846 and 882-883. 100 es y r ill m el Elektrotech- with fair weather a slow movement of the nika, 95 évfolyam, 3. Szám, 2002, pp. 82-85. 1. he risi n frm Jules Richard (ancienne bead was ideal, but during thunderstorm the maison Richard Frères) was very well known 40. Julius Fényi, Gewitter-Registrator con- ri tions of the electric fel re more r i and specialised in registering meteorological, struirt von P. Johann Schreiber S.J. (Kalocsa, and it was better to have a faster rotating bead. physical and industrial instruments. Most of 1901). 23. In 1842, the British Association for the Ad- them were equipped with a revolving drum 41. The pressure of one needle on the other vancement of Science took the empty building covered with recording paper and containing could be varied in order to modify the sensi- of an observatory which had been completed a clockwork mechanism. tivity of the coherer. in 1769 and it became widely known as the 32. For the role of Popov in the history of Kew Observatory. Francis Ronalds was the 42. Julius Fényi, ‘Über den Gewitterregistra- wireless see Charles Süsskind, ‘Popov and the inaugural Honorary Director for the next de- tor in einer neuer sher einfachen Form’, Me- Beginning of Radiotelegraphy’, Proceedings cade and founded the observatory’s enduring teorologische Zeitschrift, 1902, pp. 371-372. of the IRE, 50 (October 1962), pp. 2036-2047. re ut tion in the fel of meteorolo y n ter- Julius Fényi, ‘Über Konstruktion und Funk- restrial magnetism. 33. Some of Marconi’s biographers mention tion eines einfachen Gewitterregistrators’, that around 1892 the very young Italian in- Natur und Offenbarung, 49 (1903), pp. 612- 24. Francis Ronalds, ‘Report concerning the ventor made an apparatus of this kind when 616. Observatory of the British Association, at he s oin his frst electric l e eriments. Kew, from August the 1st, 1843, to July the 43. Max Kohl, Preisliste Nr. 21 Physikalische But we do not know much about his early sci- 31st, 1844’, in Report of the fourteenth Meet- Apparate, (Chemnitz, Max Kohl, non-dated entifc cti ity n there is no e i ence nor ing of the British Association for the Advance- but 1905), p. 800. original documents supporting this claim. ment of Science, London 1845, pp. 120-142, 44. See http://www.specula.at/adv/ see especially pp.126-127. See also Beverly 34. Enrico Boggio-Lera, ‘Sopra un appa- monat_1107.htm (accessed 28 February F. Ronalds, Sir Francis Ronalds Father of the recchio registratore delle scariche elettriche 2020). his etector h s met llic flin co- Electric Telegraph (London, 2016), pp. 132- dell’atmosfera’ , Atti della Accademia Gioe- herer and not the typical Schreiber-Fényi 134 and 434-435. nia di Scienze Naturali in Catania, Memoria needles coherer. XIII, Serie IV, Volume XIII, 1900 and Enrico 25. The electrograph should not be confused Boggio-Lera , ‘Sui miei apparecchi segnala- 45. l tin r eli e f yel se m osi- with the photo-electrograph. In the latter the tori e registratori dei temporali’, ibid, Serie tott i t r el el Természettumományi divergence of the straws of Volta’s electro- IV, Volume XIV, 1901. See also: Ladislaus Közlöny, 5. évfolyam, 8. Szám, 1901, pp. 564- scope was projected on a moveable table cov- von Szalay ‘Elektrische Signalapparate für 567. ered with photographic paper. ferne Gewitter’, Das Wetter Zeitschrift für An- 4 . l tin r eli e f yel se m osi- 26. Édouard Branly, ‘Variation de gewandte Meteorologie, 18 (1901), pp. 133- tott i t r el el s s re is tr l s l- con ucti ilit sous i erses in uences 138. ékkel’, Természettumományi Közlöny, 35. électriques’, Comptes Rendu de l’Académie 5. nrico Bo io er n utile mo ifc - évfolyam, 409. Szám, 1903, pp. 567-572. des Sciences, 111 (1890), pp. 785-787. Be- zione del coherer per gli apparecchi segnalato- fore Branly other scientists such as the Ital- 47. Horvát (2001) op. cit. note 39. See also: ri e registratori di temporali’, Atti della Acca- ian Temistocle Calzecchi-Onesti (1853-1922) http://www.gothard.hu/gttak/archive-photos/ demia Gioenia di Scienze Naturali in Catania, observed the action of electric sparks on metal categories/physmisc/images/017.jpg and Memoria XII, Serie IV, Volume XV, 1902. flin s ho e er it s the rench hysicist http://www.gothard.hu/gttak/instruments/ that clearly demonstrated that the action hap- 36. Thomas Tommasina, ‘Sur l’auto-déco- meteorological-instruments/meteorological- pened without any material connection be- hérisation du charbon…’, Comptes Rendus instruments.php (accessed 30.1. 2020). t een the s r ener tors n the flin s. de l’Académie des Sciences, 130 (1900), pp.
904-905. 27. The exact mechanism of the coherer be- Author’s email address: haviour was and still is not very well known. 37. Thomas Tommasina, ‘Sur l’étude des or- [email protected] See: Coherers, A review, A Thesis Submitted ages lointaines par l’électro-radiophone’, To be followed in the September issue by Part by Thomas Mark Cuff, 1993 https://www. Comptes Rendus de l’Académie des Sciences, 2 From Lancetta’s electrograph to the tei- researchgate.net/publication/290446135_ 131 (1900), pp. 876-878 and Eugene P. Lyle nograph and the kine-klynodograph and the Coherers_a_review (accessed 8.1.2020). Jr., ‘An Electrical Storm Prophet, An account Conclusions. of the Italian Inventor who has Coming Storm 28. It seems that the drop in resistance of a Telephone Him of their Approach’, Every-
10 Bulletin of the Scientifc Instrument Society No. 145 (2020)