102 DALTON'S AND QAY-LUSSAC'S LAW. 



applied; let the temperature be increased to t\ the piston 

 will then be forced out until the original volume v is in- 

 creased by .003665^ , where v is the volume of air at 0. 



Let v be the volume of the same mass of air at the tem- 

 perature t ; then we have 



v = v (I + .003665/!) ; 

 or, denoting .003665 by , we have 



v = v, (1 + at). (I) 



COR. 1. If Fahrenheit's scale is used, the number of de- 

 grees above the freezing point is t 32 ; and, since 180 F. 



correspond to 100 C., the expansion for 1 F. is - -^r- = 



loO 



T ^j of the volume at 32 F. The more accurate value of 

 the denominator is 491.13. 



Hence, the increase of volume = ..... ; 



492 



and, for the whole volume, we have 



492 



460 + t 

 or, v = v 493- , 



where t is the temperature on Fahrenheit's scale, and v is 

 the volume at 32 F. 



COR. 2. If v' be the volume which the same mass of air 

 assumes at the temperature t', we have 



.. 460 + t' 





Dividing (3) by (2), we have 



460 + t' 



