65J 



in which yOl) will not be far from unity. When we put 4.1 ^= i ia, 

 (1) becomes : 



_{n—\)a, _ {:n-\)mk 



in which we put a^, the attraction in the small volume i\,=zmk. 



In this f(^l) will differ somewhat more from unity than y, so that 



27 \ 

 8 will be >• y. For (ik- f)k we may now write - R7\, in which y 



8A 



is only little smaller than 1, so that we tinally get, when yA -. s = Ö 



is put : 



Q,^in-\)~Rn (1«) 



which enables us to calculate Q^, when /I and ^/, and in consequence of 

 which also 7i and 7\ are known. But as we do not know the values of ^ 

 for Hj, N,, 0,, but as we on the other hand do know those of Q^ 

 in approximation, we shall follow the reversed course, and calculate 

 11 from Qg. We can then see whether the values of \ A calculated 

 in this way are really of the expected order of magnitude, compared 

 with the already known values of \/A for elements of the periodic 

 system lying near (cf. Table II). We then get: 



^27 Tk 

 hence : 



V 27 n 



when 2, the value in Or. cal., is put for /?, which renders it possible 

 to leave also Q^ expressed in Gr. cal. The value of a refers to 

 1 Gr.mol. H.J. When therefore ^z' represents the value of one </rrt;?i-tif<o/« 

 {these values are recorded in table II), then a = 4^a\ and we get finally : 



[/Ak = Va'k X y/i + *U.e ^/Tk , ..... (2) 



when we take A and a/ both at the critical temperature. Accordingly 

 these two quantities now duly refer to 1 Gr.atom. Under the root 

 sign, however, Q^ refers to 1 Gr.mol. according to the derivation of 

 the formula. As e will always be ^y^., 0^=zy\: 6 will he soineiühat 

 smaller than unity, also when we take into account that R is not 



molecules (which can differ considerably from the spherical shape, e.g. the elongated 

 molecules of the hydro-carbons). Moreover, when the real size of the molecules is 

 calculated by another method, we also find values that are in concordance with 

 bk {^ b(i), calculated from Tk and pk, and not with ^/^bk. Cf. among others my 

 Article in These I^oc. of Oct. im4 (Vol. 17), especially p. 888 and the Note on 

 the same page. 



