AEPINITS ATOMIZED. 



837 



fluid, and leaving a defîciency of it in the rubbers to be supplied from 

 the eartli. It is curions, in Beccauia's account of lus observations made 

 abont 1760 at Garzegna in Piedmont on atmospheric electricity, to 

 read of „The mild excessive electricity of the air in fair weather/ 1 . This 

 in more modem usage would be called mild positive electricity. The 

 meaning of either expression, stated in non-hypothetical language, is, 

 the mild vitreous electricity of the air in fair weather. 



§ 8. In the mathematical theory of electricity in equilibrium, it is a 

 matter of perfect indifférence which of the opposite electric manifesta- 

 tions we call positive and which négative. But the great différences in 

 the disruptive and luminous effects, when the forces are too strong for 

 electric equilibrium, presented by the two modes of electrification, which 

 have been known from the earliest times of electric science, show 

 physical properties not touched by the mathematical theory. And 

 Taule y 1 s comparatively récent discovery l ) of the molecalar torrent of 

 resinously electrified particles from the „kathode" or resinous électrode 

 in apparatus for the transmission of electricity through vacuum or 

 highly rarefied air, gives strong reason for believing that the mobile 

 electricity of Aepintjs' theory is resinous, and not vitreous as he acci- 

 dentally made it. I shall therefore assume that our electrions act as 

 extremely minute particles of resinously electrified matter; that a void 

 atom acts simply as a little globe of atomic substance, possessing as an 

 essential quality vitreous electricity uniformly distributed through it or 

 through a smaller concentric globe ; and that ordinary pondérable matter, 

 not electrified, consists of a vast assemblage of atoms, not void, but 

 having within the portions of space which they occupy, just enough of 

 electrions to annul electric force for ail places of which the distance 

 from the nearest atom is large in comparison with the diameter of an 

 atom, or molecular cluster of atoms. 



§ 9. This condition respecting distance would, because of the inverse 

 square of the distance law for the forces, be unnecessary and the electric 

 force would be rigourously null throughout ail space outside the atoms, 

 if every atom hacl only a single electrion at its centre, provided that 



x ) Proc. Roy. Soc. vol. XIX, 1871, pp. 239, 240. 



