OF THE ALLOYS OF COPPER AND ZINC. 
537 
Table I. — Water Equivalent of Calorimeter and Contents = 4307 grammes. 
Weight of copper 
Rise in temperature 
Calories evolved per 
in grammes. 
W. 
gramme of copper. 
•672 
•279 
178-3 
1-7907 
•751 
179-8 
Mean value = 179. 
Heat of Dissolution of Zinc in Ammonium Ferric Cldoride Solution. 
Carefully sifted filings were employed in a manner similar to that described for 
copper. 
Table II. — Water Equivalent of Calorimeter and Contents = 4307 grammes. 
Weight of zinc in 
Rise in temperature 
Calories evolved jier 
grammes. 
°C. 
gramme of zinc. 
•4545 
•9768 
926 
•512 
1•1025 
928 
Mean value = 927. 
In some early experiments* the anthor found that when nitric acid was used as 
solvent, a distinct difference existed between the heat of dissolution of a mixture of 
Cn and Zn, as determined by actual ex})eriment, and the heat of dissolution cedcvlated 
from the observed values for Cu and Zn when dissolved separately. 
It is probable that this peculiarity may have been caused by the voltaic action of 
the metallic powders, in contact with each other and the liquid, influejicing the mode 
of decomposition of the nitric acid. It was therefore deemed advisable to test this 
point with the present solvent. 
Heat of Dissolution of Mixtures of Copper and. Zinc in Ammonium Ferric 
Chloride. 
The two metallic powders were weighed side by side, but not touching, on the 
same paraffined-paper tray, and after being moistened were placed in the calorimeter 
in the usual maimer. 
* ‘ Proc. Chem. Soc.,' Sept. 1899. 
3 z 
VOL. CXCVI.-A. 
