1893.] the Mechanical Equivalent of Heat, $c. 17 



Hence, adopting 15° C. as the standard temperature, the 



Specific Heat of Water = 1—0-000266 (t— 15).* 

 Also by means of equation (15) we get the following values of J : — 



Columns 4 and 6 J = 4*1939 X 10 7 



4 „ 5 J = 4-1940 x ID 7 



5 „ 6 J = 4-1940 xlO 7 



Mean J = 4*1940 xlO 7 



This value of J, as previously pointed out (equation 5), is entirely 

 independent of the value assigned to the water equivalent of the calori- 

 meter. 



And we find the w r ater equivalent of the calorimeter at 15° C. in 

 terms of water at 15° C. = 85*340 grams. The water equivalent of 

 the calorimeter at 25° C. in terms of water at 15° C. = 86 174 grams. 



Hence water equivalent = 85*340{1 + 0*000977(£-15)}. 



We can now find the capacity for heat of the calorimeter and 

 contents for any weight of water at 15°, 20°, and 25° C, and deduce 

 the value of J from each group separately. The Groups B andE are 

 experiments performed on 188*065 and 277-931 gramsf respectively. 



Table XLIIL— Values of J. 



Group. 



15° 



20° 







25° 



Mean. 



A 



4 -1940 x 10" 



4-i9*Oxl0 7 



4 -1939 x 10 7 



4 -1940 



B 



4 -1930 „ 



4 -1941 „ 



4-1949 „ 



4-1940 



C 



4-1939 



4-1938 „ 



4. 1937 „ 



3-1938 



D 



4 -1940 „ 



4-1939 „ 



4-1940 „ 



4 -1940 



E 



4-1938 



4 '1940 „ 



4 '1943 „ 



4 1940 



4-1940 



We have in the above table given the values resulting from the 

 calculation at different temperatures, for the limit of our experi- 

 mental errors is thus clearly indicated, since the values of J ought (in 

 the absence of experimental errors) to be identical at all tempera- 

 tures. The close agreement between the values from different 

 groups, *;iid from the same group at different temperatures, is a 

 satisfactc ' proof of the accuracy of our determination of the water 



* Over the range 14° to 26° C. 

 t All weights are reduced to vacuo. 

 TOL. LIU. 



