458 On the Measurement of Magnetic Forces. 



The last column of Table II. contains the values of 51 

 calculated from the observed magnetic heights h centim. by 

 means of equation 7, using the following equivalents: — 



H = 1 



Cr 



= 52-45 



N = 14-01 



Mn 



= 54-80 



= 15-96 



Fe 



= 55-88 



S = 31-98 



Co 



= 58-60 



CI = 35-37 



m 



= 58-60 



K = 39-03 



Cu 



= 63-18 



Ca = 39-91 



Zn 



= 64-88 



Mg = 23-94 



Sn 



= 117-35 





Bi 



= 207-5 



It is possible that the salts I have employed were not 

 altogether free from iron; and a very small contamination 

 with iron would produce a disturbing effect, especially with 

 small values of 51, which would be greater the smaller the 

 concentration of the salt solution. 



51 is nearly the same for the different protosalts of Mn, Fe, 

 Co, and Ni, and independent of the acid or material with which 

 the metal is combined. 



The same relationship is shown by the numerical values of 

 the atomic magnetism a, given by Herr G. Wiedemann and 

 obtained by quite different methods, which are given in the 

 following table, compared with the corresponding mean values 

 of SI. 



Table III. 





51 . 10 8 . 



Atomic 

 magnetism. 



81. 10 8 



Protosalts of manganese ... 

 Protosalts of iron 



8-328 

 6-263 

 5-756 

 2-671 

 1-295 

 0-811 



100-4 

 83-1 

 67'2 

 30-5 

 16-1 

 10-8 



00849 

 00754 

 0-0856 

 0-0876 

 00804 

 0-0751 



,, ,, cobalt 



nickel 



Potassium ferricyanide 





0-0815 



The magnetic constant, which I have denoted by 51 . 10 8 , 

 may then be obtained from the atomic magnetism a by multi- 

 plication by 0*0815. 



