Nikola Tesla - Free-Energy Devices

364 INVENTIONS OF NIKOLA TE8LA.Is then energy transmitted by independent carriers or by thevibration of a continuous medium ? This important question isby no means as yet positively answered. But most of the effectswhich are here considered, especially the light effects, incandescence,or phosphorescence, involve the presence of free atoms andwould be impossible without these.In regard to the incandescence of a refractory button (or filament)in an exhausted receiver, which has been one of the subjectsof this investigation, the chief experiences, which may serveas a guide in constructing such bulbs, may be summed up as follows: 1. The button should be as small as possible, spherical,of a smooth or polished surface, and of refractory material whichwithstands evaporation best. 2. The support of the buttonshould be very thin and screened by an aluminum and mica sheet,as I have described on another occasion. 3. The exhaustion ofthe bulb should be as high as possible. 4. The frequency of thecurrents should be as high as practicable. 5. The currents shouldbe of a harmonic rise and fall, without sudden interruptions. 6.The heat should be confined to the button by inclosing the samein a small bulb or otherwise. 7. The space between the walls ofthe small bulb and the outer globe should be highly exhausted.Most of the considerations which apply to the incandescenceof a solid just considered may likewise be applied to phosphorescence.Indeed, in an exhausted vessel the phosphorescence is,as a rule, primarily excited by the powerful beating of the electrodestream of atoms against the phosphorescent body. Even inmany cases, where there is no evidence of such a bombardment,I think that phosphorescenceis excited by violent impacts ofatoms, which are not necessarily thrown off from the electrodebut are acted upon from the same inductively through themedium or through chains of other atoms. That mechanicalshocks play an important partin exciting phosphorescence in abulb may be seen from the following experiment. If a bulb,constructed as that illustrated in Fig. 1Y4, be taken and exhaustedwith the greatest care so that the discharge cannot pass, the filamentfacts by electrostatic induction upon the tube t and thelatter is set in vibration. If the tube o be rather wide, about aninch or so, the filament may be so powerfully vibrated that wheneverit hits the glass tube it excites phosphorescence. But thephosphorescence ceases when the filament comes to rest. Thevibration can be arrested and again started by varying the