1897 - 98 .] Dr A. Galt on Heat of Combination of Metals. 149 
developed by the solution of the same quantity of the mixed 
metals in like proportions in nitric acid, is therefore 
7-04- 6*90 _ 1 
7-04 “50 ' 
The absolute amount of heat evolved in the solution of one 
gramme of the mixed metals (5T62 per cent, silver, 48 ‘38 per cent, 
copper) and of one gramme of an alloy of the same metals in the 
same proportions, calculated as usual, is 
For the mixture, 351*9 (gramme-water) heat units Centigrade. 
,, alloy, 344 9 ,, ,, ,, 
Difference, 7*0 „ „ „ 
Thus the heat of combination of *5162 gramme of silver with 
•4838 gramme of copper is 7 (gramme-water) heat units Centigrade, 
or less than half the quantity (18) obtained as the heat of com- 
bination of *7673 gramme of silver with *2327 gramme of copper. 
All the results recorded in this communication are shortly sum- 
marised on the preceding page. 
The experiments hitherto made show in each case greater heat of 
combination when the proportions of the metals in the alloy are 
nearly in the ratio of their usual chemical equivalents than when 
they are in proportions largely different from this ratio. Further 
experiments are needed to answer questions that occur in connec- 
tion with this result. I am therefore continuing the investigation, 
of which a part is described in this paper. 
