Nikola Tesla - Free-Energy Devices

184 INVENTIONS OF NIKOLA TKSLA.terminal of the lamp to one terminal of the source, and theother to an insulated body of the required size. In all casesthe insulated body serves to give off the energy into the surroundingspace, and is equivalent to a return wire. Obviously,in the two last-named cases, instead of connecting the wires toan insulated body, connections may be made to the ground.The experiments which will prove most suggestive and ofmost interest to the investigator are probably those performedwith exhausted tubes. As might be anticipated,a source of suchrapidly alternating potentials is capable of exciting the tubes ata considerable distance, and the light effects produced are remarkable.During my investigationsin this line I endeavored to exciteFIG. 122. FIG. 123.tubes, devoid of any electrodes, by electromagnetic induction,making the tube the secondary of the induction device, andpassing through the primary the discharges of a Leyden jar.These tubes were made of many shapes, and I was able toobtain luminous effects which I then thought were due whollyto electromagnetic induction. But on carefully investigatingthe phenomena I found that the effects produced were moreof an electrostatic nature. Itmay be attributed to this circumstancethat this mode of exciting tubes is very wasteful,namely, the primary circuit being closed, the potential, andconsequently the electrostatic inductive effect, is much diminished.