Communication with the Planets

Mr. Tesla on Sir Norman Lockyer — Development of the Requisite Energy.

To the editor of the Sun — Sir, In your issue of Tuesday Sir Norman Lockyer, in commenting on my observations, is reported as having stated: "Communication with Mars is absolutely outside the domain of practical science."

Before I had obtained with electrical oscillations results such as were outlined in a recent article I would have unhesitatingly agreed to this statement, but now I have the unmistakable experimental evidence before me that the transmission of a message to that or some other planet is possible and, what is more, easily practicable.

Necessity of avoiding technical details, unintelligible to the general reader, compels me to illustrate the advantage of the new means of communication over the old by a comparison which, though not exact, is sufficiently correct to convey an approximate idea. Suppose that the entire available power of Niagara, about five million horse power, should be turned into an electric arc and transformed into an equivalent amount of radiant heat and light energy to be used for the purposes of signalling. Assume, further, that the observer in a planet at a distance of fifty million miles would be able to utilize integrally the energy falling upon one hundredth of a square mile of the planet's surface. This would be a difficult if not impossible, task, but if he were successful, he would then only have 1—3,140,000.000,000,000,000th of that horse power available for the operation of his instrument.

On the other hand. let us examine how much energy could be conveyed by the methods and apparatus I have devised. In this case we should provide a conducting surface, connect it through a coll to the ground, and impress electrical oscillations upon this system. By availing ourselves of certain adjustments and artifices we should, according to my experiences, encounter no insuperable difficulties in netting up a movement of electrical energy equivalent to a rate of five million horse power, with but a small actual expenditure of energy. Supposing the observer in the planet should avail himself of similar means, we should then have, as in my system of energy transmission or telegraphy without wires, two resonating attuned circuits connected through a condenser. A great advantage would be at once secured. since the energy does not diminish with the square of the distance, as with light, heat or Hertzian rays, but in a linear proportion to the same.

Estimating the capacity of the condenser formed by the earth. the planet and the intervening medium. I find that we should be able to transmit in this manner to Mars, at intervals, energy at the rate of 1—50,000th of a horse power, which in the tuned circuit on the planet, by skillful construction. and adjustment of the apparatus could be intensified to a rate of one-fifth of one horse power, and a considerable portion of this accumulated energy would be available for the operation of the receiving instrument.

The attainment of this enormous rate of energy delivery is made possible by the fact that in using these novel means we should not dissipate the energy of the transmitter uselessly in all directions through space, as we should when employing rays: We should simply transmit electrical stresses through the medium. It is as if we had a weightless. elastic bar extending from our globe to the planet, and as if we were transmitting energy by pushing this bar back and forth. The above rough estimate is obtained by ignoring the disturbing influences of the sun and of other planets, but by making all due allowances we could still convey to its place of destination an amount of energy many million times that possible with radiant light or heat. As far, then, as our ability of communicating with Mars is concerned, far from believing it impossible. we are justified in considering it practicable.

Why should Sir Norman Lockyer doubt that the energy would reach the planet? Does not the fact that electric disturbances are produced in the earth by changes in the sun offer a sufficient warrant? While I do not consider myself infallible, I feel confident that I am neither capable of mistaking earthquakes for novel electrical manifestations, nor incapable of noting what might have escaped the attention of others. did not state that I had obtained a message from Mars. I only expressed my conviction that the disturbances I observed were of planetary origin. It does not follow that they could he detected by magnetic instrument. These are delicate only in a certain sense: in another sense they are very crude, Sir Norman Lockyer asks what ground I have for assuming Mars inhabited? I do not hesitate to admit that I am convinced of it. Perhaps part of my conviction is derived from the perusal of Sir Norman Lockyer's admirable papers. I am sorry he attaches no value whatever to my observations.

NIKOLA TESLA.
NEW YORK, Jan. 9.