( 41 ) 



Reversely we may now also think the corresponding values of 

 o>, x and '/'„, to be solved for any given pair of values of ir and 6, 

 though explicitly I his is impossible, so that we shall have to be 

 satisfied with the set of equations from (2) to (6). 



The further discussion of these equations, particularly with regard 

 to the branch C„A of the plaitpoint line, in connection with the 

 longitudinal plait, will be found in the paper, which will shortly 

 appear in the Arch. Teyler. There the course of the pressure is also 

 examined, which we no further discuss here. It is only desirable to 

 calculate the data for the "third" critical temperature C Q , viz. ,r 

 and T — not because these data are indispensable for the following 

 considerations, but because Keesom includes them in his considerations, 

 and it is profitable in any case to know something concerning the 



relation — or — . 

 -* i i 



As v = h for the point C„, so y = — = 1, and the equation of the 



('../-projection of the plaitpoint line (Aug. 17, 1905, p. 146 ; Teyler 

 I and II), viz. 



(l_»)»(l_2*-8«(l-*)fi«»)4-8( 9 )+«Xl-y) , a-*)(l-2*)+ 

 , (y. + «)'(l-y)'(l-3y) _ n 



w(l —a) 

 is reduced to 



1 — 2.v — 3# (1 — .« )wto = 0, 



or as y = (1 -j- n.v) tu, and hence co = , to 



1 -j nx 



(l-2*.Kl+n« i )-8*,(l-« i )« = 0, 



from which follows : 



*o — " (') 



n 



From this is seen that the situation of C„ depends only on the 



value of n or 1 -f- n = --. 

 h i 

 The corresponding value of T a is found from (la). For y = 1 

 we find : 



RT, = — i*.(i-«.xi-*.) , l 

 b 1 



in which a> = and z. = rau> (</) -j- .«,■„). 



1 -f n<e a 



8 «V 

 As T, = — — — (see above), we have ; 



