ON THE MECHANICAL EQUIVALENT OF HEAT 403 



Temperature. Mean Specific Heat. 



24 to 100 -0915 



26 to 100 -0915 



25 to 100 -0896 



13 to 39 -0895 



14 to 38 -0885 



9 to 41 -0910 



To reduce these to the mean temperature of to 40, I have used 

 the rate of increase found by Bede for copper. They then become, for 

 the mean from to 40, 



0897 

 0897 

 0878 

 0893 

 0883 

 0906 



Mean -0892 -00027 



As the capacity of the calorimeter is about four per cent of that of 

 the total capacity, including the water, this probable error is about -g-oW 

 of the total capacity, and may thus be considered as satisfactory. 



I have also computed the mean specific heat as follows, from other 

 observers : 



Copper between 20 and 100 nearly. 



0949 Dulong. 



0935 Eegnault. 



0952 Eegnault. 



0933 Bede. 



0930 Kopp. 



0940 



This reduced to between and 40 by Bede's formula gives -0922. 

 Hence we have the following for the calorimeter: 2 * 



24 The cast brass was composed of 28 parts of copper, 2 of tin, 1 of zinc, and 1 of 

 lead. The rolled brass was assumed to have the same composition. The solder was 

 assumed to be made of equal parts of tin and lead. 



