ADIABATIC CHANGES OF MOIST AIR NEUHOFF 437 



tion of condition for gases and for each component of the mixture 

 we have the equations V p' = RT and 



Vp" = x R T 



e 



respectively. Hence by addition we obtain 



Vp = (l + ~ )R.T (2) 



as the equation of condition for the mixture and by division we 

 obtain 



P" 



X = £ r 

 P' 



for the mixing ratio, which is proportional to the ratio of the partial 

 pressures of the two components, so that if x is constant then this 

 ratio must also be constant. It is often advantageous to introduce 

 the barometric pressure p into the equation of condition and in this 

 case R is specially designated by an index letter /?. 



If in this last equation we substitute for the pressures whose ratio 

 enters therein the heights of the mercurial columns, then the mixing 

 ratio is expressed in grams by the equation 



X = 622 -f- 



p — e 



Let e m be the pressure for saturated aqueous vapor then we have 



x m = 622 6m 

 p-e m 



by the use of which expression the quantity of aqueous vapor con- 

 tained in 1 + x kilograms of saturated moist air can be determined. 

 The quantity x m required for saturation is a function of the baro- 

 metric pressure p and also of the temperature, since the pressure 

 for saturation e m = f(t) is dependent on the temperature alone. 

 The quantity x in grams of the aqueous vapor contained in (i -f x) 

 kilograms of saturated air is computed according to this formula 

 for the temperatures + 30 C. to — 30 C. ordinarily occurring in 

 meteorology and for different barometric pressures p, and is given 

 in table 1, columns 4 to 9. This table contains also in the second 



