504 
Proceedings of the Royal Society 
period when man was as yet the contemporary of the mammoth, 
and when the reindeer extended its range into Southern Europe — 
is to be found in portraits of that mammoth and of that reindeer 
scratched upon fragments of their tusks and horns. A.nd yet there 
is no physical obstacle to the exercise of this power by animals ; 
the beak and the claw are implements as effective as the rude 
flint point of the savage, and there is nothing in the physical 
conformation of the Gorilla to prevent that flint point from becom- 
ing in his hand an implement of design. 
The following Gentleman was elected a Fellow of the 
Society - 
Rev. H. Calderwood, LL.D., Professor of Moral Philosophy in the 
University of Edinburgh. 
Monday , lhth March 1869. 
DAVID MILNE-HOME, Esq., Vice-President, in 
the Chair. 
The following Communications were read : — 
1. Motion of a Palladium Plate during the formation of 
Grahams Hydrogenium. By James Dewar, Esq. 
(Received 1st March 1869.) 
Graham, in continuing his exhaustive researches on diffusion, 
has recently examined the relation of gases to various colloid septa. 
The remarkable discovery of Deville and Troost of the permeability 
of platinum and iron by hydrogen at a red heat, he has expanded 
into a general examination of the relative rates of passage, at 
high temperature, of the various gases through different metallic 
septa. Further, he has proved that different metals have a 
specific occluding power over certain gaseous elements, retaining 
them in combination at low temperatures, although the absorption 
took place at a red heat. Of the many astonishing discoveries 
made during the course of these investigations, probably the most 
remarkable is the occlusion of hydrogen by palladium. This metal, 
whether in the form of sponge or hammered foil, when heated and 
