62 ART. 10. — K. IKEDA : STUDIES ON THE 



(Sa. In such cases r<^ must be so small that pr^ remains negligible 

 in comparison with other pressures. Then we have 



(C'oc)t = -^ • (48) 



"■a 



and 



-+1 (413) 



{1. 



AVhen ti^. and 7:^^ are known for one temperature then they 

 are known at least approximately for the range of 30° to 50° 

 above and below that temperature. I mean that it is possible 

 to evaluate T^ and 1\ in the equations 



0--?) 



because h has approximately the value of 10.0 for all chemical 

 species, when the pressure is given in atmospheres, as shown in 

 § 2 (c), of the preceding chapter. 



The quantities D and %, which determine ^ as a function 

 of temperature can be evaluated when the tension and density 

 of the saturated vapour of the pure associated component are 

 given for another temperature. In the cases where the vapours 

 have normal densities, only the knowledge of the vapour tension 

 is required. 



When the four characteristic quantities D, %, To. and 2p 

 are known, the state of chemical equilibrium in the system com- 

 posed of the associated compound alone or Avith other normal 



