CRITICAL COEFFICIENT 49 



T 



according to which the quotient ^ is proportional to the 



* t 



volume b at the absolute zero, and accordingly like that 

 quantity, of essentially additive nature. 



T 

 This quotient -=/ has therefore a special meaning, and is 



called by Guye l the critical coefficient. It may be approxi- 

 mately obtained by addition from the following values : 

 C = 1.35 H = 0.57 <j) = o 87 O = 1.27 



Cl = 2-66 N = i.6 N=i-86 P = 3-01 



Double linkage = 0-88. Triple linkage = 1-03. 

 Let us take first, as example : 



Propyl formate HC< n p -p- 



4C + 8H + () + ( I] ) = 5.4 + 4-56 + 0-87 + 1-27 = 12-1. 

 The experimental results are : 



T k = 533' 8 5 p k = 42-7 atm. ; 



so that 



- 533* _ K , 



- 41-7 ' 



It is of importance that here, too, we have an indication 

 as to molecular magnitude, since, e.g., acetic acid (C 2 H 4 O 2 ) 

 gives 



T k 273 + 3^1-65 



=:- = - - = 104 observed against 



Pk 57-i 



2C + 4H + (J) + O = 2-7 + 2-28 + 0-87 + 1-27 = 7-12; 



a large deviation, which is in agreement with the fact, 



demonstrated on all hands, that acetic acid in the critical 



state is partly associated. The formula 



CH 3 CH 3 



HO 



would lead to 



= 5-4 + 4\56 + 3'48 = 13-44- 



1 Theses, 1891. 

 D 



