Nikola Tesla - Free-Energy Devices

288 INVENTIONS OF NIKOLA TESLA.Of all these phenomena observed with currents, or electricimpulses, of high frequency, the most fascinating for an audienceare certainly those which are noted in an electrostatic fieldacting through considerable distance; and the best an unskilledlecturer can do is to begin and finish with the exhibition of thesesingular effects. I take a tube in my hand and move it about,and it is lighted wherever I may hold it; throughout space theinvisible forces act. But I may take another tube and it mightnot light, the vacuum being very high. I excite itby means of adisruptive discharge coil, and now it will lightin the electrostaticFIG. 163. FIG. 164.field. I may put it away for a few weeks or months,still it retainsthe faculty of being excited. What change have I produced in thetube in the act of exciting it? If a motion imparted to atoms, itis difficult to perceive how it can persist so long without beingarrested by frictional losses and if a strain exerted in the dielec-;tric, such as a simple electrification would produce, it is easy tosee how itmay persist indefinitely, but very difficult to understandwhy such a condition should aid the excitation when wehave to deal with potentials which are rapidly alternating.