Nikola Tesla - Free-Energy Devices

HIGH FREQUENCY AND HIGH POTENTIAL CURRENTS. 177vanes mounted over it (Fig. 114), be connected to one terminal ofthe coil either one or both ends of the platinum wire being connectedthe wire is rendered almost instantly incandescent, andthe mica vanes are rotated as though a current from a batterywere used. A thin carbon filament, or, preferably, a button ofsome refractory material (Fig. 115), even if it be a comparativelypoor conductor, inclosed in an exhausted globe, may be renderedhighly incandescent and in;this manner a simple lamp capableof giving any desired candle power is provided.The success of lamps of this kind would depend largely on theselection of the light-giving bodies contained within the bulb.Since, under the conditions described, refractory bodies whichare very poor conductors and capable of withstanding for a longtime excessively high degrees of temperature may be used,such illuminating devices may be rendered successful.It might be thought at first that if the bulb, containing theFIG. 114. FIG. 115.filament or button of refractory material, be perfectly well exhaustedthat is, as far as it can be done by the use of the bestapparatus the heating would be much less intense, and that ina perfect vacuum it could not occur at all. This is not confirmedby my experience; quite the contrary, the better the vacuumthe more easily the bodies are brought to incandescence. Thisresult is interesting for many reasons.At the outset of this work the idea presented itself to me,whether two bodies of refractory material enclosed in a bulb exhaustedto such a degree that the discharge of a large inductioncoil, operated in the usual manner, cannot pass through, could berendered incandescent by mere condenser action. Obviously, toreach this result enormous potential differences and very highfrequencies are required, as is evident from a simple calculation.