146 Proceedings of Royal Society of Edinburgh. [sess. 
32 cubic centimetres of nitric acid were used as the solvent ; its 
density was 1*270 at 15° C., and its specific heat was taken as 
‘703. The apparatus used and the method of experimenting were 
exactly the same as formerly, and the results obtained in ? the 
several experiments are shown in the subjoined table. 
Heat of Solution of 1 gramme (*7673 gramme of Silver mixed with 
*2327 gramme of Copper) of the Mixed Metals and of 1 gramme 
of the Alloy. 
Mixture. 
Alloy. 
Temperature of the Acid before and 
Temperature of the Acid before and 
after Solution. 
after Solution. 
Before. 
After. 
Difference. 
Before. 
After. 
Difference. 
C.° 
C.° 
C.° 
C.° 
C.° 
C.° 
11*90 
17*58 
5*68 
12*00 
17*16 
5T6 
14*05 
19*75 
5*70 
12*00 
17*14 
5*12 
11*90 
17*59 
5*69 
11*92 
17*06 
5*14 
Mean Difference, . 
5*69 
Mean Difference, . 
5*14 
The heat of combination of any quantity of copper and silver 
in the proportions stated, expressed as a fraction of the heat 
developed by the solution of the same quantity of the mixed 
metals in like proportions in nitric acid, is 
5*69 - 5*14_ 1 
5*69 “103* 
The absolute amount of heat evolved in the solution of one 
gramme of the mixed metals (76*73 per cent, silver, 23*27 per 
cent, copper) and of one gramme of an alloy of the same metals 
in the same proportions is 
Tor the mixture, 186*5 (gramme-water) heat units Centigrade. 
,, alloy, 168 5 ,, ,, ,, 
Difference, 18*0 „ „ „ 
