( 170 ) 



."' ,. .?; 1 — .V 

 With the aid of the relation e '' = - — '— . we find from this; 



i A', ,u^ 



For the iiillection point wc have about ,i\ = 0,HH and .i\ = 0,40. 

 For ;i"xi we find then about — 1,5. Taking into consideration tliat 

 the pUxce of the point of inflection cannot be determined accurately, 

 and that with change of the .i', of this point at the same time also 

 its .Uj is changed, the agreement may be called satisfactory. 



The in Let «re carhontetvachlond-acetone. 



These two substances, carbontetrachioride and acetone were chosen 

 with a view to the critical pressure, which is about the same for them. 



Kow Van der Waals ') has derived, that for ii s, = constant the 

 relation between /> and ,i\ is represented by a straight line, that 

 between ^> and .v^ by a hyperbola. 



On the supposition tiiat at low temperature for /(',i may be written : 



''r 



■*' ; for ^1,: è (^A + ^^r) <^"f^ ^''^^^ ^^^^ ♦•^^ relatioji of 



MRT d,v, 



Galitzine— Bekthelot ri^„=V/aia, holds good, the condition ƒ*'.„ = 

 constant involves, that the critical pressures of the components are 

 the same. 



Now the abo\e mentioned improved approximation for ^/V, has 

 already been given by Van dkh Waals himself instead of the one 

 mentioned here ; moreover the relation a^^ = \/a^ a^ has already 

 been discussed and rejected by Kohnstamm. *) It is therefore not 

 surprising, that a strong deviation from the straight line and the 

 hyperbola was found for this mixture '). 



The i)A\d\ diagram is given in Table YI. Acetone is to be consi- 

 dered as admixture : 



1) These Proc. Ill p. 168-161). 



2j KoHxsTAMM, Proefschiift, biz. 99. 



3) From the survey of the investigated mixtures given by Kohnstamm, Zeilschr. 

 f. Phys. Chem. XXXVI. 1, it appears also, that equality of critical pressure of 

 the components does not necessarily involve the existence of a straight line for the 

 p = /'{x'i) line. 



