409 



(5) L^= ~ 0^, For sufficiently high temperatures tiiat curve may 

 be regarded as straight. Tiie assumptions of the former paper involve, 



Fis. 2. 



however, that in the neighbourhood of O /-^ as a function of T 

 is curved more or less according to the ratio of T^ to OJ^. In an 

 appreciable measure this curvature may only be expected for high 

 values of ö„, such as for the monatomic ferromagnetic elements. 



The observations by Weiss and FoËx ') concerning nickel, iron ') 

 and cobalt actually point to a change of x^' as indicated by Fio-. 2. 

 It is true, that Weiss and FoËx represent y~^ approximately by two 

 portions of straight lines, at least for a certain region of temperatures 

 from the CuRiE-point upwards ; but they remark expressly, that for 

 instance ') for nickel the inclination of the portion of the graph 

 which is nearest to has no determinate value. 



In accordance with tiiis Honda and Takagi') find the x~'.^-gi'aph 

 for nickel between over 400° C. and 550° C. gently curved. Further 

 according to Honda and Takagi this portion passes continuously into 

 the nearly straight portion for higher temperatures. If we abstract 



1) P. Weiss and G. Foëx, Arch. sc. phys. et nat. (4) 31 (1911), p. 89. 



2) Gf. for this, hov,'ever, A. Preuss, Diss. Zurich (Techn.Hochsch.) 1912, p. 64, 



3) Cf. p. 95 I.e., for iron p. 97, cf. also in particular for cobalt p. 101. 



*) KöTARó Honda and Hiromu Takagi, Science Reports Tohoku University Sendai 

 (1) 1 (1913), p. 229. 



