﻿334: Intelligence and Miscellaneous Articles. 



another kind, such as chemical affinity, and the gravitating forces 

 of ponderable masses are quite insignificant, the work of dissocia- 

 tion must be quite defined by valency-charge, number of molecules 

 in the molecular weight, and molecular diameter. As regards the 

 work of gravitation von Helmholtz has shown * that it quite dis- 

 appears in comparison with the electrical work, since the electrical 

 forces of the charges are many million times greater than the 

 gravitating forces of the corresponding material carriers. As it will 

 be seen that the w 7 ork of dissociation calculated from the magni- 

 tudes mentioned agrees in the order of their magnitude with those 

 determined experimentally, specially chemical forces can play no 

 great part in comparison with electrical forces, and we must con- 

 clude that chemical affinity is essentially an electrical property of 

 the smallest particles. 



M. F. Bicharzt has formerly shown that in the case of 

 nitric tetroxide we arrive at plausible values for the sphere of 

 action of the molecules, if we consider the work needed for dis- 

 sociation of N 2 4 into 2N0 2 as an electrical one done against the 

 attractions of the elementary charges ; in this he assumes that 

 such elementary charges attach to the free valency of the 

 monovalent group 



O 



— o 



It must be of interest to make such a calculation for the im- 

 portant case of an elementary gas. In this respect hydrogen 

 and iodine vapour have the recommendation that we have definite 

 values for the heat of dissociation. According to Helmholtz's 

 electrochemical theory in the case of hydrogen the two atoms hold 

 together in the molecule, because one of them possesses at its 

 position of valency a positive quantum of electricity, which it would 

 have for example in an electrolyte; the other, on the contrary, 

 has had to change its positive charge, in an electrolytic process for 

 instance, for an equal negative charge, and is thus negatively 

 charged. Hence the hydrogen molecule is externally electrically 

 neutral. Iodine is analogous. The conception of a molecule con- 

 sisting of a positive and a negative atom has been successfully 

 applied by MM. W. Giese, A. Schuster, J. J. Thomson, Elster 

 and Geitel, &c, to explain a series of phenomena of gas-discharges. 



We have experimental data about the dissociation of hydrogen. 

 In 1880 E. "Wiedemann, in his experiments on the thermal and 

 optical deportment of gases under the influence of electrical 

 charges, has determined the heat W necessary to resolve the 

 molecules of hydrogen which show the band-spectrum into the 

 individual atoms, which then show the well-known line-spectrum. 



* H. v. Helmholtz, Vortrage und Beden, ii. p. 317 (1884). 

 t Sitzungsberichte der Niederrhein Gesellschaft zu Bonn, Jan. 12, 1891 ; 

 Verhandl. der Thys. Gesellschaft zu Berlin, June 2Q>, 1891, p. 73. 



