﻿218 Prof.M. P. Eudskion 



hydrogen molecule is concerned, for any energy lost by the 

 temporary and transient union of hydrogen and palladium 

 is at once gained during its escape on the other side of the 

 partition. But the hydrogen in expanding, which it does on 

 passing through the partition, loses energy, and hence, on the 

 whole, energy will probably be lost during the process. It 

 is to such theories, I think, that we must look to explain the 

 passage of hydrogen through a palladium diaphragm. 



(2) In answering the question why the pressure raised by 

 the entering hydrogen is never equal to that of the atmosphere, 

 I think it must be admitted that the gas contained in the 

 palladium vessel is not without influence on the passage of 

 the hydrogen. A diminution of the pressure of the external 

 hydrogen by the addition of nitrogen considerably increases 

 the partial pressure of the internal hydrogen. Here the 

 action of external nitrogen apparently neutralizes partially 

 the effect of the internal nitrogen, and more hydrogen pene- 

 trates the metallic diaphragm. With gases other than 

 nitrogen in the interior, the pressure of the hydrogen 

 becomes more nearly equal to that on the exterior. The 

 constancy of the results, however, proves that the deficiency 

 is not due to experimental error. 



This whole subject is full of difficulty. Experiments are 

 in progress on the absorption of gases by platinum, and on 

 the passage of gases through other metallic diaphragms, which 

 may ultimately render an explanation possible. But I have 

 thought it desirable to place these experiments on record, 

 incomplete as they are, rather than wait for a complete 

 solution to the problem. 



I cannot conclude without acknowledging the able manner 

 in which my late assistant, Mr. Percy Williams, has aided me 

 in carrying out these experiments. 



XXIII. Note on the Rigidity of the Earth. 

 By M. P. Eudski, Odessa*. 



PEOF. NEWCOMB f has estimated the Eigidity of the 

 Earth from the observed 427 days' J period of the Vari- 

 ations of Latitude, and found it to be somewhat greater than 

 that of steel. His estimation being a rough one, I have 

 undertaken a more precise calculation with the help of the 

 formulas of Thomson and Tait. 



* Communicated by the Author, 

 t Monthly Notices Astron. Soc. 1892, pp. 336-341. 

 \ The recent investigations of the astronomers of Poulkova confirm 

 also this period. 



