6 AET. 10. — K. IK EDA : STUDIES ON THE 



2. The energy of the sohition is the sum of the energies 

 of the components (in the liquid state) under the same 

 pressure and at the same temperature. 



These conditions may be expressed by the following equations : 



V= n{u, + 9uv.^+ , (1) 



E = ')7,s, + oi.,e,+ , (2) 



where V and jE" are the volume and energy of the solution, 7ii, 



7i2, are the number of mois (gramme-molecules), ^ij-^a? 



the so-called molecular volumes, and sy, s-z energies j^er mol 



of the components <Si, ©25 • These conditions must hold 



at all temperatures and pressures. 



The first condition is what is called by van dee Waals 

 the law of Amagat. While the law of Dalton is a so-called 

 " Grenzgesetz " to which the gas mixtures approximate the more 

 closely the greater the rarefaction, the law of Amagat has a 

 ^vide range of application, gases under high pressures being known 

 to obey it in some cases. It is quite probable that it would 

 hold, at least aj^proximately, for most gaseous mixtures in which 

 chemical reaction is excluded, because even liquids form solutions 

 with extremely small change of volume when they are uuas- 

 sociated. 



The second condition is also fulfilled at least approximately 

 by these liquid mixtures, because the heat disturbances observed 

 on mixing are mostly quite small, being in some cases apparently 

 nil. Hence it is also highly probable that gases under pressures, 

 high or low, should fulfill the condition more or less closely. 



When these conditions are satisfied, the chemical potentials 

 of the components have a very simple form just as in a mixture 

 of ideal gases : 



