Nikola Tesla - Free-Energy Devices

366 INVENTIONS OF NIKOLA TES1.A.ous impression upon the eye.It is a fact that such a coil excitesphosphorescence under almost any condition and at all degreesof exhaustion, and I have observed effects which appear to be dueto phosphorescence even at ordinary pressures of the atmosphere,when the potentials are extremely high. But if phosphorescentlight is produced by the equalization of charges of electrifiedatoms (whatever this may mean ultimately), then the higher thefrequency of the impulses or alternate electrifications, themore economical will be the light production. It is a longknown and noteworthy fact that all the phosphorescent bodiesare poor conductors of electricity and heat, and that all bodiescease to emit phosphorescent light when they are brought to acertain temperature. Conductors on the contrary do not possessthis quality. There are but few exceptions to the rule. Carbonis one of them. Becquerel noted that carbon phosphoresces atat a certain elevated temperature preceding the dark red. Thisphenomenon may be easily observed in bulbs provided with arather large carbon electrode (say, a sphere of six millimetres diameter).If the current is turned on after a few seconds, a snowwhite film covers the electrode, just before it gets dark red.Similar effects are noted with other conducting bodies, but manyscientific men will probably not attribute them to true phosphorescence.Whether true incandescence has anything to do withphosphorescence excited by atomic impact or mechanical shocksstill remains to be decided, but it is a fact that all conditions,w T hich tend to localize and increase the heating effect at the pointof impact, are almost invariably the most favorable for the productionof phosphorescence. So, if the electrode be very small,which is equivalent to saying in general, that the electric densityis great ; if the potential be high, arid if the gas be highly rarefied,all of which things imply high speed of the projected atoms,or matter, and consequently violent impacts the phosphorescenceisvery intense. If a bulb provided with a large and smallelectrode be attached to the terminal of an induction coil, thesmall electrode excites phosphorescence while the large one maynot do so, because of the smaller electric density and hencesmaller speed of the atoms. A bulb provided with a large electrodemay be grasped with the hand Avhile the electrode is connectedto the terminal of the coil and itmay not phosphoresce ;but if instead of grasping the bulb with the hand, the same betouched with a pointed wire, the phosphorescence at once spreads