601 



which with Ab = O passes into 



' 27 ^'i+ii^ {i-'/jy ' ^ ^ 



If ^=1 (single molecules), then RT/c duly becomes = -, 



27 b^ 



but for ^ =1 (double molecules) RTk becomes = 2 X ~^)- 



Bat it is again immediately seen that RTk certainly does not linearly 

 change with 2:(14-/^), i.e. witli van uer Waals's 1 + .r, as the latter 

 assumes on p. 1078 of his treatise. 



For the remaining factor is indeed again = 1 for /i = and 

 /i=l, but it is 3450: 3125 = 1,106 for ii='U; =1445: 1296 = 

 = 1,115 for /?=V,; and =1125 : 1024 = 1,099 for t'? = V,. The 

 deviation can therefore again amount to 9 7o. in comparison with 

 11 7o for V]c, but in opposite direction. This deviation too is more 

 pronounced, when Lb differs from 0. 



With regard to the value of ph, at last, we find : 



The factor of — r — duly has the value 1 both for 3 = and 



27 b,^ -^ 



/?=1; but becomes =4617 : 3125 = 1,477 for ^=7,; =375: 



: 243 = 1,543 for /? = 7^ ; '^"d = 189 : 128 = 1,476 for ^=7,. 



Accordingly the deviation from unity is very considerable — for 



/?=Yi moi'e than 54 7o- Hence there is no longer any question of 



1 a 

 an approximate equality to —- — , as van der Waals supposes he 



u I 0, 



may assume, (p. 1078 I.e.). And this amount can still increase for 

 A^ not = 0. 



1) If it is taken into account that «i = V4. «2» ^i = Vs ^2» -^'^^ becomes as it 



8a,.. 

 always did = ^ r, in which cij and &2 now refer to a double molecular quantity. 



