at constant volume aiid high pressure. 
89 
Other experiments gave values from *412 to ‘508, the particular 
example being chosen because it was about the mean value. 
The usually accepted value for the specific heat at constant 
volume is about T72. Joly has shown, however, that the specific 
heat does increase with the pressure, and he found that an 
increase in pressure from 7'2 atmospheres to 21 '66 atmospheres 
caused an increase in the specific heat of from T6841 to T7386. 
This increase is not great, but, if it went on at the same rate, 
it would make the specific heat about '4 at 500 atmospheres. 
The gas used in the bulbs was made from coke and was dried by 
being passed through towers containing calcium chloride. There 
might have been a small amount of water remaining. The makers 
certify it to be chemically pure. 
The author proposes to continue the work, using such other 
gases as can be easily sealed in the bulbs. 
