358 Dr. J. R. Ashworth on the Calculation of 



In general symbols, 



Let Y= The component of intensity o£ magnetization, 

 or, of electric polarization parallel to the 

 directive force, 



X = The applied force, 



T = The absolute temperature, 



/zX 

 « = o~^> where fju is the magnetic or electric 



moment of the molecule and R^ the gas 

 constant for one molecule, 



then . y i 



^r = cotha— -, (14) 



Y being the maximum value of Y. 

 For small values of Y this becomes 



v _ Y o a _ Y aX 



3 " 3KT' w 



or X 



Y 



CT, (16) 



C being the constant y^*. 



This equation has the same form as the gas law. 



In passing it may be noticed that if \x be multiplied by 

 the number of: molecules in unit volume and the product be 

 put equal to Y , and if the appropriate value of R be used , 



wt. 



a formula which differs from the one employed above in the 

 calculation of maximum values by the insertion of the 

 factor 3 in the numerator under the root sign ; when it 

 is applied, all the saturation values given above must be 

 multiplied by \/3. In magnetism the agreement between 

 the theoretical and observed saturation values would remain 

 the same as before if it be assumed that iron and cobalt 

 have each three atoms in the molecule and that the molecule 

 of nickel contains six atoms. (See Kunz, Phys. Rev. 

 vol. xxx. p. 359.) 



