270 Mr. J. H. T. Roberts on the 



reflected back into the gaseous mixture from the polished 

 walls goes primarily to increase the energy in the vibratory 

 degrees of freedom of the molecules, and that this excess is 

 then partitioned off into the translational and rotational 

 degrees during molecular collisions. 



The writer desires to tender his thanks to Prof. Hopkinson, 

 to whom he is greatly indebted for so much kindly advice 

 and valuable criticism upon the main suggestions made in 

 this paper. 



XXXI. The Disintegration of Metals at High Temperatures. 

 Condensation Nuclei from Hot Wires. By Joseph H. T. 

 .Roberts, M.Sc., Oliver Lodge Prizeman ; late Isaac 

 Roberts Scholar ; Oliver Lodge Research Fellow in Physics 

 in the University of Liverpool *. 



[Plate II.] 

 Introductory. 



IN a letter to ' Nature/ August 29th f, the writer gave a 

 brief account of experiments upon the disintegration of 

 metals, more particularly the platinum metals, and put 

 forward the theory, with a short account of evidence to 

 support it, that the disintegration of the platinum metals was 

 due to direct oxidation. The following paper contains an 

 account of the continuation of those experiments, and shows 

 how the results provide further evidence in support of the 

 same view. Throughout this paper the word disintegration 

 simply means loss of weight ; it is not intended to convey 

 any theory as to the manner of the loss. 



The disintegration of platinum and iridium is a phenomenon 

 which cannot have escaped the notice of users of platinum 

 pyrometers, and platinum and iridium furnaces. Many 

 direct experiments have been performed by different investi- 

 gators upon the loss of weight of wires of the platinum 

 metals in different gases ; as a result of these experiments, 

 the great influence of oxygen upon the rate of disintegration 

 has long been recognized, but in view of the very general 

 opinion of scientists (in some cases clearly expressed J) that 

 platinum does not, under any circumstances, combine 

 directly with oxygen, there has been a diffidence in 

 suggesting that the influence of the oxygen is other than 



* Communicated by the Author. 



t This letter was also reproduced and discussed by ' Engineering/ 

 October 25, 1912, p. 577. 



% Deville and Debray, Comptes Rcndus, 1878, vol. lxxxvii. p. 441. 



