1892.] on Alternate Currents of High Potential and Frequency. 645 



energy to be dissipated by molecular impact or bombardment. The 

 action is thus explained : — 



When an insulated body connected to a terminal of the coil is 

 suddenly charged to a high potential, it acts inductively upon the 

 surrounding air, or whatever gaseous medium there might be. The 

 molecules or atoms which are near it are, of course, more attracted, 

 and move through a greater distance than the further ones. When 

 the nearest molecules strike the body they are repelled, and collisions 

 occur at all distances within the inductive distance. It is now clear 

 that, if the potential be steady, but little loss of energy cau be caused in 

 this way, for the molecules which are nearest to the body having had 

 an additional charge imparted to them by contact, are not attracted 

 until they have parted, if not with all, at least with most of the 

 additional charge, which can be accomplished only after a great 

 many collisions. This is inferred from the fact that with a steady 

 potential there is but little loss in dry air. When the potential, 

 instead of being steady, is alternating, the conditions are entirely 

 different. In this case a rhythmical bombardment occurs, no matter 

 whether the molecules after coming in contact with the body lose the 

 imparted charge or not, and, what is more, if the charge is not lost, 

 the impacts are only the more violent. Still, if the frequency of the 

 impulses be very small, the loss caused by the impacts and collisions 

 would not be serious unless the potential were excessive. But when 

 extremely high frequencies and more or less high potentials are used, 

 the loss may be very great. The total energy lost per unit of time 

 is proportionate to the product of the number of impacts per second, 

 or the frequency and the energy lost in each impact. But the energy 

 of an impact must be proportionate to the square of the electric 

 density of the body, on the assumption that the charge imparted to 

 the molecule is proportionate to that density. It is concluded from 

 this that the total energy lost must be proportionate to the product 

 of the frequency and the square of the electric density ; but this law 

 needs experimental confirmation. Assuming the preceding considera- 

 tions to be true, then, by rapidly alternating the potential of a body 

 immersed in an insulating gaseous medium, any amount of energy 

 may be dissipated into space. Most of that energy, then, is not 

 dissipated in the form of long ether waves, propagated to considerable 

 distance, as is thought most generally, but is consumed in impact and 

 collisional losses — that is, heat vibrations — on the surface and in the 

 vicinity of the body.. To reduce the dissipation it is necessary to 

 work with a small electric density — the smaller the higher the 

 frequency. 



The behfiviour of a gaseous medium to such rapid alternations of 

 potential makes it appear plausible that electrostatic disturbances of 

 the earth, produced by cosmic events, may have great influence upon 

 the meteorological conditions. When such disturbances occur both 

 the frequency of the vibrations of the charge and the potential are in 

 all probability excessive, and the energy converted into heat may be 



