M. R. Bunsen on the Law of Absorption of Gases. 119 



appreciable compared with the volume of gas, the alteration 

 which the absorption causes in the composition of the unabsorbed 

 gas must be brought into the calculation. 



Let us next consider the alterations which a mixture of two 

 gases undergoes by absorption, supposing that all the volumes 

 of gas employed are reduced to 0°. Let the total volume of gas 

 under the pressure P be V ; in the unit volume of this gas let 

 there be v volumes of the first gas, and v x of the second. Let 

 the absorption-coefficient of the first gas at the observed tempe- 

 rature be a, and that of the second /3, and the volume of absorb- 

 ing liquid h. Further, let the total volume of the gas remaining 

 after the absorption be V l under the pressure P, ; and lastly, let 

 the unit volume of this residual gas contain u volumes of the 

 first, and u { volumes of the second gas. 



The volume V contains vY volumes of the first gas at the 



uVP 



pressure P, or j— ^ volumes at m- 76. This volume is sepa- 

 rated by absorption into two parts : the first part, x, remains 

 behind after the absorption as free gas ; the second, x i; is that 

 absorbed by the water. The amount of this latter is determined 

 by the law of absorption ; the unit of liquid absorbs the volume 

 u under the pressure m> 76; hence under thepressurePj,A volumes 

 of water will absorb 



0-76 * 



As, however, the first gas is expanded by mixture with the 



V P 



second from x to . * - 1 , the amount of gas absorbed by h is, in 



consequence of the partial pressure, 

 ctlix _ 



-y—-X v 



Hence 



ahx _ wVP 



or 



vYV 



and by similar reasoning, the volume of the second gas is 



