Chemistry and Physics. 317 
potential or ented | resistance. When the saci passes 
through these regions, electric potential is obse The heat 
state and the electrical state are interconvertible town of energy, 
ma Saehery according to the state of the body.—Ann. der ny aa 
und Chemie, No. 8, “1881, p. 582. 
4. Micr op hotekd action of Selenium cells.—Dr. oe Mossle 
led by the theory that one and the same ray of light may have- 
heating, chemical ty luminous effects, has eben ue behavior 
of selenium under the influence of the electrical current. It was 
ni 
with a cell composed of zine, selenium and copper, a polari- 
zation of about 0°4 volt. was observed and a current was obtained 
long after it was separated from the primary battery. A careful 
examination of the connections between selenium and copper in 
the form of cells invented by vise and Tainter, and modified by 
- and pers which consists of a fer ahd a sn ed on 
Moser therefore sees no reason for separating selenium from other 
bodies and “ no prospect of finding an unknown power or a new 
relation of forces in this substance.”—PAil. Mag., Sept., 1881, 
p. 212. 
On the stresses caused in the Interior a the Larth by the 
Weight of Continents and Mountains; by G. H. Darwtn, F.R.S. 
—In this paper I have considered the subject of the solidity and 
Strength of the materials of which the earth is formed from a 
point of view from which it does not seem to have been hitherto 
discussed, 
he first part of the paper is entirely devoted to a mathematical 
investigation, based upon Sir Wi liam Thomson’s well-known 
paper on the rigidity of the earth.* “The ti are consists of 
&summary and discussion of the preceeding work. 
The existence of dry land proves that the saat? s surface is not 
a figure of Acer aes appropriate for the diurnal rotation. see 
the interior. of the earth must be in a state of stress, and a 
the land as not sink in, nor the sea-bed rise up, the istieade 
*“Thomson and Tait’s Nat. Phil.” § 834, or ‘ Phil. Trans.,” 1863, p. 573. 
