Specific Heat at Constant Pressure and Constant Volume. 373 

 By reducing, this equals 



5- 1 79-47 (1+^-003665)^1? degrees Cent., 



which equals the increase of temperature of the air resulting 

 from its compression ; and from this value the increase of pres- 

 sure resulting from the increase of temperature may be cal- 

 culated, since air tends to expand "003665 of its volume for 

 each increase of a degree Centigrade beyond zero. 



1 + { * l + TT 79 ' 47 ( 1 + V003665) - dv I -003665 

 '"' 1 + ^003665 



(1 + ^*003665)/l + S'79-47 x -003665 * dv ) 

 = 1 + ^-003665 



= 1 + 5- 1 -29126- <&. 



H v 



Therefore when a volume of air is compressed through dv, 

 it acquires a pressure adiabatically; that is 1 + W "29126 -dv, 



e pressure the air would have if compressed isothermally. 



By equating this value with 1 H ^ dv, the value of 



=s^ may be obtained ; since 



1 + 



H v \H Jv 



.-. § -29126= §-1; 



TT 1 



'• H ~l--29126~ 14:iUy0, 



TT 



So that the value of — ^ or 7, determined by this method, would 

 appear to be about 1*41. 



