238 



PROFESSOR W. A. TILDEN ON THE SPECIFIC HEATS OF MI/1 ALS. 



Series X. 



This result is very slightly lower thau the result of the previous series. 



Experiments on Pure Nickel. 



For the metal used in these determinations I am indebted to the kindness of 

 Dr. L. MOND, F.R.S. It had been deposited twice from the carbonyl compound by 

 heating in a glass tube. It was afterwards found to contain a minute quantity of 

 sulphur. In the form in which it was received it was, doubtless, somewhat porous, 

 and when heated in a vacuum it gave off a small quantity of gas,* and this is 

 probably the chief reason why the results obtained in estimating the specific heat are 

 somewhat less uniform than those obtained with fused cobalt, and, as will be seen 

 later, with fused nickel. The deposited but uufused nickel was not acted upon 

 perceptibly by steam at 100. 



Series III. 

 Pure Nickel. Deposited from Ni(CO) 4 . 



* Ackworth and Armstrong found hydrogen in Russell's pure nickel, but not in fused commercial 

 nickel nor in Russell's pure cobalt, though in the latter case it was surmised that hydrogen had been 

 originally present, but the metal examined had undergone oxidation, all but the piece used in their 

 experiments for solution in nitric acid, and which was "extremely dense and compact." (' Journ. Chem. 

 Soc.,' 1877 [2], p. 82.) 



