Tesla On The Electrical Transmission Of Energy

Friday, July 21, 1893
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ENGLISH Mncnsmo AND WORLD or soraNoE= JULY 2% 1893- TESLA ON TBI ELECTRICAL THAN S- MISSION OF ENERGY. THE following extract from the long leetura dehvered recently by Mr. Nikola Tesla will be found of espeeial _interest from several points of new:--Some enthusiasts have expressed their belief that telephcny_to any distance by induction through the air is possible. I cannot stretch my imagina- tion so far ;_but I do firmly believe that it is prac- ticable to disturb, by means of werful machines, the electrostatic condition of tg; earth, and thus irruisiuit intelligible signals :uid perhaps power. lu fact. what is there against the carrying out oi sur-lr n. scheme? We now knrnv that electric vilwrnimi may be rmnsmiaeil tlrmuglr rr single cnsrlscem-_ \Vhy, then, not try to avail ourselves of the carrlh for this pur ose? We uccd not be frightened hy the idea. eip distance, To thc wcztry wanderer counting thc inile-posts the earth may appear very large; but to that happiest nf all men, the astro- nomer, who gazes at the heavens and by their standard judges the nmgnituile of our globe, it appears very small. And so I think it must seem to the electrician, for when he considers the speed with which an electric disturbance is propagatell through the earth, :ill his ideas of clistancexirusi completely vanish. A point of great importance would be, iirst, to know what is the capacity of the earth and what charge does it contain if electrified? Though We have no positive evidence of u charged body exist- ing in space without other ogipositely eleetrilied bodies being near, there is a air probability that the earth is such a. body, for by whatever process it was separated from other bodies-and this is the accepted view of its origin-it must have retained a charge, as occurs in all processes of mechanical separation. If it bc :L charged body insulated in space, its capacity should he extremely small, less diss one-umasssach of s farad, Bat urs rr;-,sr strata of the air are conducting, and so, perha s, is the medium infree space beyond the atmospliere, and these may contain an opposite charge. Then the capacity might be incompcrahly greater. In any case, it is of the greatest importance to get an idea of rvhugdguantity of electricity the can con- tains. It is ` cult to sn whether we shall ever ac- quire this necessary knowledge, but there is hope that we may, and thatis by means of el ctrieal resonance, If ever we can ascertain at what period the eartli‘s charge, when disturbed, oseillates with respect to an opposifely electrified system or known circuit, we s all know a. fact possibly of the greatest im- portnnce to the welfare of the human race. I pro- pose to seek for the period by means oi an electrical oscillator, or s. source oi a ternating electric cur- rents. One of the terminals of the source would be connected to earth, as, for instance, to the city water mains, the other to an insulated body of large surface. It is possible that the outer conducting mr strata, or free space contains an opposite charge, and that, together with the earth, they fcnn n con- denser of very Large ea city. In such msc the period of vdnation may siivery low, and an alter- nating dynamo ms/chine might serve for the purpose oi the experiment. I would then transform Lho current to a potential as high as it would be found possible, and connect the ends ol. the high tension secondary to the ground and to the insulated body. By varying the frequency of the currents and cars- fully 0 serving the potential of the insulated belly, and watching for the disturbance at various neigh- bouring points of the earth’s surface, resonance h ‘rf r. 1: 5 inight be detected. Should, as the majority ni scientific men in all robahility believe, the period be extremely small, sian u d limo machine would not do, and aévroper electrical” oscillator would have to be produce , and perhaps it might notbe possible to obtain such rapid vibrations. But whether this be gssible or not, and whether the earth contains a c rge or not, and whatever rnsy be its period of vibration, it certainly is possible-for of this we have daily evidence-to produce some electrics] disturbance suflicienily powerful to be perceptible by suitable instniments at any point oi the earih's surface. Assume that a source of alternating currents S le connected, as in the figure, with one of its iennimls to enrth (conveniently to the water nmins) and w.|l\ the other to u body of large surface P. \\'h<-n the electric oscillation is set up, there will be u mme- ment of electricity in and out of P, and nllcrnnling currents will pass through the earth, converging lu

JULY 21, 1893. ENGLISH MECHANIC AND WORLD OF SCIENCE or diverging from the point C where the groinnl' connection is inznlc. In this manner neighbouring points on the ear!h's surface within u certain irulius \\‘ill he ilisturbeil. But the ilisturlmlice will dilniuish with the distuuce, und the ilistuncc nt which the effect will still be perceptible will de nd on the quantity of electricity set in motion. éiiice the body I’ is insulated, in order to displace u, con- sidemble quantity the potential of the source must be excessive, since there would be limitntinns us to the surfuee of P. The conditions might bc adjusted so that the generator or source S will set up the some electrical movement us though its circuit were closed. Thus it is certainly practicable to impress :rn electric vibmtion at least of n. certain lou' period npl? the earth by means of proper mn.chiner3'. At w t distance such fx vibration ` ht be mn e per- ceptible mn only be conject\\rcdfm]§l\:\ve on :mother occasion considered the question how the eurth :night behave to electric disturbances. There is no doubt thnt, since in such un experiment the elec- trical density at the surfnce couh be but extremely small consi ering thc size of the earth, the nu' would not uct us u very disturbing factor, und there would be not much ener lost through the action of the air, which woulfybe the case if the density were §cn.t. '1‘heoretically, then, it could not r quire 0. great nruount of euer y to produce :i disturbance perceptible nt rent istauce or even all over the surface of the ggobc, Now, it is quite certain that ut uuy point within a certain radius of the source S a properly adjusted self-induction and cnlnmcity device cnu be ect in nction by resonance, But not only cnn this be done, but another source .SH similar to S, or any number of sucli sources can be set to work in synclironism with the latter :ind the vibration thus iukensitled :ind s :read over 3 large aren, or n How of electricity prodhiccfl to nr from the source S, if the some be 01 opposite phase to the source S. I think thot, beyonl doubt. it is possible to operate electrical devices in n city through the ground or pipe system by rcsnnnuco from un elcctriczvl oscillator locnteil ut ai vculrail wine. not the ,»»-uelimi snlutinu uf um 1"-~|.|em| would he ol' iiicompairulrly suuillcr bcnciit to umn than the renlisitiou of the scheme ol trzlzmruitting ' intelligence nr perhaps power to any distance throu h the earth or eurirouiug niediuin. If this is at :ill possible ilismnce docs not mean anything. I Proper :ippmntus must first be produced by menus ot which the problem can lm xittncked, :ind I here devoted much thought to this subject. I :im firmly convinced that it can be doue,:iuil hope that wo' shrill live to sen it done.