11G 



ment by Weiss and Piccard, whereas, as was found by Perkier 

 and Kamerlingh Onnes, on the assumption of a negative molecular 

 field with unchanged molecular rotatory energy a correspondence of 

 the inclinations can only be obtained by the aid of a new hypo- 

 thesis (unless the difference in inclination should be ascribed to a 

 systematic difference of experimental origin). 



§ 3. Tlie susceptihility of liquid oxygen and the application of 

 the quantum-theorji to paramagnetism. The susceptibility of liquid 

 oxvgeu being measured over a considerably larger temperature range 

 (from 65.°25 K. to 9ü.°l K.: Kamkrltngh Onnes and Perkier, Comm. 

 W. 116 ; from 70.°2 K. to 90M K. : Kamerlingh Onnes and Oosterhuis, 

 Comm. N". \^'2e), than was possible for the mixtures treated in § 2, 

 it is important to investigate whether the data which are available 

 about liquid oxygen can be represented also with the aid of the 

 relations (1) and (4). In table III the corresponding data have been 

 put together. 



As Perriek and Kamerlingh Onnes observe, account has to be 

 taken of the change in density of liquid oxygen. For the reduction 

 of 0^ to the same density use was made of the result which will 

 be derived in § 5 from the observations concerning the above mix- 

 tures considered in connection with those concerning oxygen, inz. 

 that at these large densities f\ is proportional to q'^'-'^ . 



TABLE Ilia. 



Specific susceptibility of liquid oxygen 

 (Kamerlingh Onnes and Perrier). 



^0., 



1,23.-, 



^calc. 

 with <9„ = 232 



106 



V 1.235/ 



0-C 



64.25 

 70.86 

 77.44 

 90.1 



229 

 233 

 235 

 232 



282.6 

 271.7 

 261.3 

 240.9 



+ 2.3 

 - 0.3 

 -1.7 

 + 0.2 



mean 232. 



The agreement l^etween observation and calculation may be con- 

 sidered sufficient. This conclusion is supported by the observations 



