Nikola Tesla - Free-Energy Devices

144 INVENTIONS OF NIKOLA TESLA.heating may be practically due to the bombardment alone. Hepointed out also that the skin effect is largely modi lied by thepresence of the gas or of an atomic medium in general. Heshowed also some interesting experiments in which the effect ofconvection is illustrated. Probably one of the most curious experimentsin this connection is that in which a thin platinum wirestretched along the axis of an exhausted tube is brought to incandescenceat certain points corresponding to the position ofthe striae, while at others it remains dark. This experimentthrows an interesting light upon the nature of the strife and maylead to important revelations.Mr. Tesla also demonstrated the dissipation of energy throughan atomic medium and dwelt upon the behavior of vacuousspace in conveying heat, and in this connection showed the curiousbehavior of an electrode stream, from which he concludes thatthe molecules of a gas probably cannot be acted upon directlyat measurable distances.Mr. Tesla summarized the chief results arrived at in pursuinghis investigations in a manner which will serve as a valuablemost inter-guide to all who may engage in this work. Perhapsest will centre on his general statements regarding the phenomenaof phosphorescence, themost important fact revealed in this directionbeing that when exciting a phosphorescent bulb a certaindefinite potential gives the most economical result.The lectures will now be presented in the order of their dateof delivery.