ELECTROPLATING AT HOME www.americanradiohistory.com May, 1953 NEWNES PRACTICAL MECHANICS 317 M AY, 1953 PRACTICAL EDITOR VOL. XX F. J. CAMM No. 233 MECHANICS Owing to the paper shortage "The Cyclist," "Practical Motorist," and "Home Movies " are temporarily incorporated. By The Editor Fair Comment 3-D DEVELOPMENTS filmsand wouldrequireonlymildpurpose. Cameras have gradually STEREOSCOPIC films have beenalteration to existing apparatus. acquired more lenses and up to six are much discussed in recent weeks Great strides are being made almostnow accommodated on the lens turret, innewspapersasthoughtheyevery month in the science of television,providing a wide and flexible range of were a modern invention.The fact isone of the latest being automatic pictureviewing angles.Dangerous research can that from the earliest days of the cinema-control, whichwasrecentlydemon-be made more safe by the use of suitably tograph there have been literally dozensstrated in London. sited cameras.Electrically, experiments ofinventionsforthree-dimensional In many TV areas to -day a certainconnected with circuit breakers operating films.In almost every case the vieweramount of signal fading occurs.Someat high voltages are too dangerous for is expected to wear special glasses, andplaces are far worse than others, but inanyone to approach nearer than 2ooft., the three-dimensional films being shownmany districts, at some time during anwhereas a camera can be placed into to -day, with two exceptions, still makeevening's entertainment, controlshaveposition only 3ft. from the main rotor use of that system, which has manyto be reset due to a change in signalof a 40o kV generator, providing the defects, not the least of which is that ifstrength. It is claimed that automaticengineerswithaclose-upof what one's eyes are not perfectly matched, orpicturecontrol TV willprovideahappens whenageneratorisshort if there is myopia or astigmatism in onesteady picture of constant contrast andcircuited through tests. of them, the picture is not seen in threebrilliance even though signal strength Remote control of a large crane by dimensions but becomes blurred. varies by as much as z0 to i. radio and TV permits the crane to handle Althoughcolourfilmshave made dangerousproductssuchasatomic This was proved convincingly at thematerial in bulk, and the operator can marked progress in the last twenty yearsdemonstration, and although the picture see what the craneisdoing without they are still far from perfect.No oneblacked out completely on an ordinary has produced a film in natural colours ;TV receiver due to signal fading, theexposing himself to danger. theyalllook lurid and unreal.Theautomatic picture controlset was not same applies to colour photography. noticeably affected. DEVELOPMENTS IN SAFETY AT SEA Withtelevisiontheprojectionof A further advantage with this new set pictures in colour has made some pro- device for saving lives at sea isthe " interference damper," a deviceANEW gress-no more than that.Such de-which makes for a considerable reduc- was recently demonstrated in Lon- monstrations asI have witnessed, in-tion of " snowstorm " interference.Indon.It consists of a transmitter fitted cludinga demonstration by thelatethe bright areas of the picture streaks ofinto a small box no larger than 12in. x Bairdandanother by a well-knowninterferencestaywhite,butindark7in. x Sin. deep, bolted to the underside television manufacturer, merely indicateareas where they have shown up whiteof the thwarts or seats of a lifeboat. that colour television is possible at somebefore on the screen they now become The only action that the unfortunates distant date. in the boat have to take is to mount the grey and are practically invisible. rod typeaerial by a simple plug-in PROJECTION TV TV AS AN AID TO INDUSTRYaction and then turn the handle of the UNTIL someone candiscover a meansA RECENT application of TV is astransmitter until a small neon light comes of amplifying light as we can now an aid to industry and science inon and continue turning the handle until amplifysound,thedevelopmentof the signal is seen to be going out.This observation techniques, and the threeis shown by means of another neon in- projection TV will be hampered, becausecompanies manufacturing TV cameras dicator which blinks accordingtothe as the picture is " blown up " the lightareallproducing apparatusforthis diminishes and the picture takes on a morse signal being radiated. woolly aspect.This is not particularly Part of the signal is a continuous tone noticeablewithpictures upto,say, SUBSCRIPTION RATES and rescuing ships can use it for direction loin. square, but forbig screen tele- including postage for one year findingandnavigating ontothose vision the problem becomes more diffi- Inland - -- - 14s. per annum. adrift. cult of solution.It is my view, however, Abroad---- 14s. per annum. It is true that, by regulation, wireless that eventuallyall TV receiverswill Canada- - 13s. per annum. transmitters have to be fitted in a pro- Editorial and Advertisement Office :" Practical make useof atinytube whichis Mechanics," George Newnes, Ltd., portionof theship'slifeboats, and cheaply replaced, in conjunction with Tower House, Southampton Street, Strand, W.C.2 although it may be possible in a large 'Phone : Temple Bar 4363 anopticalsystemincorporatingthe Telegrrns :Newnes, Rand, London. number of cases to find the lifeboat with Bresnel lens. Registered at the G.P.O. for transmission by the transmitter, it is virtually impossible, 3-D television is already on the way Canadian Magazine Post. in anything like a heavy sea, for a flock Copyrightinalldrawings,photographs and and is being considered by the BBC. articles published in "Practical Mechanics " is of lifeboats not so equipped to keep Viewers will not need special glasses, speciallyreserved throughout the countries within hail of the transmitting boat. asimpleattachmenttothe signatorytotheBerne Convention and the Itis merely U.S.A. Reproductions or imitations of any of with the object of equipping viewing screen.This system can easily these are therefore expressly forbidden. these other boats that this transmitter be adapted for the cinema showing of has been developed.-F. J. C. www.americanradiohistory.com 318 NEWNES PRACTICAL MECHANICS May, 1953 . LITCY OTLEFE gATEE The Theory of Electroplating and its Practica Application in the Home Workshop ELECTROPLATING is the process of By E. HARRIS MORGAN, B.Sc. proton and one electron. This is the atom depositing on a base metal a thin, of hydrogen. In Fig.tthere are shown uniform, adherent, non -porous coating the atoms which result by taking first one, of some other metal, from a solution of aelectronisanextremelyminuteparticle then two, then three protons, and soon.It suitable salt of this metal, by the use of an(about t/t800th of the mass of a proton)will be noticed that in the nucleus of all the electric current. possessing unit negative electric charge. atoms, except that of hydrogen, there appear a Now the atom iselectrically neutral andnumber of neutrons. It so happens, that in Reasons for Electroplating therefore must contain an equal number ofthe atoms illustrated in Fig. t, the number of There are many reasons why such a coat-unit positive and unit negative charges, or,neutrons is the same as the number of protons ing may be advantageous. For reasons ofto put it another way, an equal number ofbut this is not necessarily always the case.In mechanical strength and ease of working, theprotons and electrons. The positive charges,the case of the element lithium, it will be seen two metals most commonly used in engineer- that the extra electron takes up a new path, ing are iron (including steel) and brass. Both Orbit and that we now have two orbits. Each iron and brass are subject to attack by gases Nucleus additional electron enters the second orbit of the atmosphere. In the case of iron, rust- 0- ELECTRON until there are eight electrons in this orbit, ing with consequent loss of strength occurs, and then a third orbit is started.Itis an O while in the case of brass, tarnishing spoils 0 PROTON (P) interesting fact that the elements with eight the appearance of the article.Electroplating electrons (or an octet) in their outermost orbit both iron and brass with a coating of some are all chemically inert ;that is to say, they () NEUTRON (N) Helium suitable metal, such as nickel or chromium, Hydrogen do not join with other elements to form com- prevents the process of tarnishing and at the pounds. same time provides a surface of permanent and attractive lustre. In the case of car lamp reflectors, the coating serves another Electrolytes purpose.The reflector is easily spun from There are two main classes of compounds, brass, but brass tarnishes rapidly and would electrolytes and non -electrolytes.Itis the require constant polishing, and, added to this, electrolytes with which we are concerned in brass has a yellow colour.Coloured objects Lithium Beryllium Boron electroplating, and the theory which follows possess their colour by virtue of the fact that is confined to this class of compound. they absorb and abstract certain wavelengthsFig.1.-Diagrams illustratingthestructure The atoms of active elements, in combining from white light ;thus coloured objects do of the atoms of a few of the elements. to form compounds, either give or receive not reflect all the light which falls upon them. electrons so that the outermost orbit possesses By coating brass with a " white " metal, a a complete octet.In Fig. 2a the atoms of higher proportion of the light is reflected andorprotons,are clusteredtogetherinthepotassium and chlorine are shown diagram- the reflector is thus made more efficient.Thecentre of the atom together with a certain matically. Itwillbenoticedthatthe metals commonly used for plating reflectorsnumber of neutrons,and this cluster is knownpotassium atom has one electron in its outer- are chromium and silver.Whether electro-as the nucleus. Around the nucleus revolvemost orbit, and the atom of chlorine has seven plating beautifies an object is a controversiala number of electrons equal to the numberelectronsinitsoutermostorbit. When subject with which I am not going to dealof protons in the nucleus.