﻿44 Dr. Asliworth on Magnetic Temperature Coefficients 



treated in the same way, lie very nearly on a single curve 

 (the broken curve of fig. 2), which is very similar to the full 

 curve in the same figure. 



It follows from the concordance of the three curves of 

 fig. 1, when plotted on a scale of reduced temperatures, that 

 the change of fractional magnetic intensity for each of the 

 ferromagnetic elements is the same for the same interval on 

 this scale, or, that the coefficients of residual magnetism of 

 the ferromagnetic elements in corresponding states are in- 

 versely proportional to the absolute critical temperatures. 



6. This result is precisely the law for the change of 

 density of liquids with variation of temperature, and it is of 

 interest to inquire if the coefficients on a reduced scale 

 of temperature are of the same order of magnitude. 



Since the physical constants of water are well known, it 

 may be selected as a typical liquid for comparison. The 

 variation of its density w T ith temperature has been determined 

 by several observers, and according to Cagniard de la Tour 

 its critical temperature is 390° C, Hirn's value being rather 

 higher. Adopting 390° C. or 663° A as the critical tem- 

 perature, I have constructed Table III., in which the fractional 

 density of water at different temperatures is placed side by 

 side with the fractional magnetic intensity of nickel which 

 has nearly the same critical temperature. To make the 

 comparison easier, I have treated the density of water as 

 0'945 at 21° C, which is numerically the same as the mag- 

 netic intensity of nickel at that temperature. 



Table III. 



Comparison of Fractional Intensity of Nickel and 

 Fractional Density of Water. 



Temp. C°. 



6/0,. 



21 



•44 



107 



•57 



135 



•62 



165 



•66 



193 



•70 



223 



•75 



250 



•79 



280 



•84 



310 



•88 



320 



•89 



Nickel. 



•945 

 •90 



■38 

 .86 

 •84 

 •80 

 •76 

 •71 

 •66 

 •64 



Water. 



•945 

 •91 



•88 

 •85 

 •83 

 •79 

 •75 

 •71 

 •65 

 •63 



Difference. 

 Nickel— Water. 



±'00 

 -•01 

 ±00 

 + •01 

 + •01 

 + •01 

 + •01 

 ±•00 

 + 01 

 + 01 



Critical temperature of nickel=388° C. 

 ol'^ater=:39U c C. 



