( 45 ) 



For x = 2' ,. / must lie > ' B , and then t »/t q <C2 1 ' 4 - Etc., etc. 



The larger therefore the value of a, — the smaller in other words 

 the value of z - the smaller also the limiting value of P., above 

 which a minimum is to be expected, the sooner this will therefoie 

 appear, and at comparatively large corresponding values of ^/tv 



But as we already observed in § I, all this refers only to the 

 existence or non-existence of a minimum in the line C„ C\. That this 

 line has the shape in question, depends on quite different circumstances 

 — viz., as I already showed in June 21, 1905, p. 33 — 48 for 6, = b 3 , 

 and further extended to the general case in later papers (particularly 

 Teyi,er I), it depends only on this, whether for the given value of n 

 the value of is found above that at which the plaitpoirit line lias 

 a double point or not. And the criterion for this is fig. 1 of Oct. 25, 

 1906 (see also Teyi.er II). If we are above the limiting line DBPAC', 

 we are in the region of type 1, where one of the branches of the 

 plaitpoint line runs from C„ to C, (the other from .1 to 6', — - see 

 e.g. fig. 1 of Juni 21, 1905 and fig. 1 of Jan. 25, 1906). And beloto the 

 limiting line we are in the region of type II (or III), where the 

 branches of the plaitpoint line are 6\ C, and AC . But for all this 

 consult the papers cited. 



April 1907. 



Appendix. After I had written the above considerations, the Con- 

 tinuation of the last cited paper by K. Onnes and Keesom appeared 

 in These Proceedings, April 25, 1907, p. 795—798. There a condi- 

 tion is derived for the appearance of a minimum plaitpoint tempera- 

 ture, which is identical with that which I published Jan. 25, 1906 

 (formula (3), p. 581), at which result also Verschaffelt (These Proc, 

 April 24, 1906, p. 751) arrived a month later. 



For on p. 796 K. O. and Keesom give the condition (see formula (2)): 



\y-=- 



V a. 3 



— l + l/l +3 



'2 'A 



Now in my notation °i/ ff] = X \ H (see above; I denote viz. the 

 component with the smallest value of a by the index 1 ; Keesom 

 does the reverse). Further ^/j, = '/>, s o that the above formula 

 passes into 



l/H 



1 + 1/1 + s /y 



from which follows: 



