CHEMICAL THEORY OF SOLUTIONS. PART I. 65 



On tracing the curve of partial pressure for acetone and 

 drawing the tangent to the curve at x = 0, the following ap- 

 proximate vakie has been found for the vapour pressure of pure 

 C3H0O 



7:^ = 160. m.m. 



The tangent of the angle which the curve of partial pressure 

 of ether makes with the x axis has been found to be nearly 



\ dx J\ 



400. 



The molar fraction of CoHcO in pure acetone is 



(C'a), = ^ = 0.435 



and in consequence that of (C.,Hr,0)v amounts to 



((7ß)i = 0.565 



V can now^ be determined by equation (45) 



(^\ 



V dx Jx 400 _-. 



^" 18^-6 +1 = 3.04. 



((7pX 0.565 



There is no doubt that v — 3. 



With these data the value of ^ for 0°C. is determined to be 



CV 0.43.5' mir^p 



^ = — ^ = .-.rr- = 0.1456. 



From the total pressure curve we get values but slightly 

 different. 



7:^ - lC-2 and {C,\ = 0.430 



