i 
Electric Origin of Gravitation. 685 
We may conclude that the y rays either consist of particles 
practically devoid of electric charge, or are of the type of 
Rontgen rays, or have a special character of their own hitherto 
unknown. | 
The dissimilarity between R6ntgen and y rays in connexion 
with the ionization of gases and vapours, and in the character 
of the secondary radiations, is probably due to the fact that 
the Rontgen pulses are more broad than those which con- 
stitute the Yrays. The differences are decreased when harder 
bulbs are used, and the resulting pulses are more thin. 
Theoretical reasoning still supports the view that the 
expulsion of the @ particles must be accompanied by pulses 
similar to those set up on the stoppage of the cathode particles; 
and, until there is definite evidence to the contrary, it is 
reasonable to suppose that these pulses, analogous to the 
Rontgen rays, constitute the y rays. 
In conclusion the writer has pleasure in acknowledging the 
kind help and advice received from Professor Rutherford. 
McGill University, Montreal. 
27th Aug., 1904. 
LXVIII. Zhe Electric Origin of Gravitation and Terrestrial 
Magnetism. By WitL1AM SUTHERLAND%*. 
| ee conception that the inertia of matter and that of 
electricity must be identical makes it probable that 
gravitation has an electric origin. As cohesion and rigidity 
have been shown to be essentially electric properties of matter 
(Phil. Mag. Dec. 1902; May 1904), the investigation of 
gravitation from a similar point of view invites attention. 
In a short paper read before the Royal Society of Victoria 
in 1877, on a connexion of causation amongst electricity, 
magnetism, and gravitation, my late brother Alexander 
argued that the inverse square law of force indicated such a 
connexion. With this idea as a starting point we may pro- 
ceed as follows :—Suppose matter to be formed of pairs of 
electrons $b whose inertia constitutes the inertia of matter. 
Such a pair of electrons, or molecule of electricity, when 
forming a component of the ether, I have proposed to call a 
neutron. Let us write down the force between two such 
doublets in a more general form than that usually assumed. 
Suppose them to be at a distance + apart which is great in 
comparison with the distance between % and b in each puair. 
Let the charge of % be e,, and of h be e,. Let the attraction 
* Communicated by the Author. 
Phil. Mog. 8. 6. Vol. 8. No. 48, Dec. 1904. 38 
