412 Dr. J. R. Ashworth on the Theory of 



power in micro-volts per degree; and the last column is the 

 reduced micro-volts per degree. The thermo-electric power 

 of nickel is negative to lead, and as it is convenient to have 

 the values positive for comparison with the thermo-electric 

 powers of iron, another, the fourth, column has been in- 

 serted in which the numbers in the third column have been 

 -converted into positive quantities by subtracting them from 

 23'3, the maximum thermo-electric power for nickel. 



Fig. 4 shows at a glance the results of this table. Up 

 to the reduced critical temperature, unity, the two curves 

 show a general agreement, but above this point there is a 



x *= HtCKELl-. 



o = /Ron. 



Qlrso/ate Thmfre rater re • 



6 -S 



considerable divergence which is perhaps due to a change in 

 iron, the molecule of which appears to undergo a subdivision 

 at or near the critical temperature. 



There is, on the whole, evidence that corresponding states 

 approximately hold for iron and nickel in relation to thermo- 

 electric power. 



6. Theory of an Intrinsic Magnetic and Molecular Field. — 

 Returning now to the problem of the intrinsic field, the results 

 of the experiments which have just been described lead to 

 the conclusion that the magnetic intrinsic field has not the 

 enormous magnitude which has been assigned to it, but on 

 the contrary has probably a very small value. Nevertheless, 

 the effects of temperature on ferro-magnetism demand an 



