in Chemical Combinations. 



503 



Table XVI. — Experiments on the Heat evolved by the Mercury 

 Spiral in the can of water used in the experiments of Table XIV. 

 Pile of 5 cells. 2 lbs. 11 oz. of water in the can. 



From the above tables we obtain for the capacity for heat of 

 the jar of dilute sulphuric acid used in the experiments of 

 Table XIII., 



2-9987 41-402 loeQ „ __ KC 

 2^9256 X 47064 Xl283 ' 7 = llo °- 



For the quantity of heat due to 



A-C 

 A-B 



xBC, 



42-642 3-2607 



1^38 X 2^2181" X 1283 7 " 3441 8 - 

 And for the actual quantity of heat evolved in the electrolysis, 

 40-381 



23-38 



xll55 = 1994°-9. 



Hence 3441°-8-1994°-9 = 1446°-9, the quantity of heat ab- 

 sorbed during the electrolysis of a quantity of sulphate of water 

 corresponding to 0*04243 of a gramme of hydrogen. 



The quantity of heat absorbed by the electrolysis of a quantity 

 of sulphate of water corresponding to a gramme of hydrogen will 

 therefore be 31101°. 



Two other series of experiments conducted in precisely the 

 same manner, excepting that in the former of the two the capa- 

 city for heat of the jar of dilute acid was obtained by the method 

 of mixtures, gave 34212° and 32358° respectively, as the he|t 

 absorbed per gramme of hydrogen liberated. The mean of the 

 three results is 33557°. 



A small portion of this quantity of heat absorbed is that due 

 to the removal of water from the dilute acid ; but the correction 

 on this account is so exceedingly small as to be hardly worth 



