ON THE MECHANICAL EQUIVALENT or HEAT 397 



Water in A while running, 309-0 by No. 6163. 



Calor. before 391-3; temperat. 314-5 by 6166. 



Calor. after 3129-0; temperat. 308-3 by 6166, and 378-5 by 6163. 



Air about 21 C. 



Therefore, water lost 0-078, and calorimeter gained 5. Hence the 

 capacity of the calorimeter is 39. 



Another experiment, more carefully made, in which the range was 

 greater, gave 35. 



The close agreement of these with the estimated amount is, of 

 course, only accidental, for they depend upon an estimation of only 

 0-08 and 0-12 respectively. But they at least show that the water is 

 delivered into the calorimeter without much change of temperature. 



A few experiments were made as follows between ordinary tempera- 

 tures and 100, seeing that this has already been determined by Reg- 

 nault. 



Two thermometers were placed in the calorimeter, the temperature 

 of which was about 5 below that of the atmosphere. The vessel B 

 was then filled, and the water let into the calorimeter, by which the 

 temperature was nearly brought to that of the atmosphere; the opera- 

 tion was then immediately repeated, by which the temperature rose 

 about 5 above the atmosphere. The temperature of the boiling water 

 was given by a thermometer whose 100 was taken several times. 



As only the rise of temperature is needed, the zero points of the 

 thermometers in the calorimeter are unnecessary, except to know that 

 they are within 0-02 of correct. 



June 18 

 Temperature of boiling water, 99 -9. 



Calor. before 2684-7; temperat. 259-2 by 6166, and 248-3 by 6165. 

 Calor. after 2993-2; temperat. 381-0 by 6166, and 363-4 by 6165. 



259-3 = 18-568, or 18-555 when corrected for stem. 

 248- 3 = 18 -564, or 18 -551 when corrected for stem. 

 381-0 = 28-054, or 28-065 when corrected for stem. 

 363-4 = 28 -055, or 28 -066 when corrected for stem. 



Specific heat 28 100 _ , . Of)24 

 Specific heat 18 - 28 ~ 



Other experiments gave 1-0015 and 1-0060, the mean of all of which 



