170 Prof. G. Wiedemann on the Magnetic 



Experiment showed that, even when precipitates were formed, 

 it was ahnost invariably likewise equal to M. Thus, among 

 others, were observed mixtures of: — 



ma. 7)1^. ma + mb.^l ohs. 



Ferric chloride and sulphocyanide \ -. n. ^ _4^.o _ i ^.i i a.c* 



of potassium j ~ 



Ferric chloride and ferrocyanide ) o w^ a ^ c^a ^ 01 i 

 p , . "^ >24*b — 4-l = 20'O 21*1 



or potassmm j 



Ferrous sulphate and ferricyanide \ \\Q.(\^i^.,J__A^.^ ^a.q 



of potassium / ' 



Cuprous sulphate and ferrocyanide ) 4..s_4..i _ n-7 n-X 



of potassium J ~ 



Cobaltous nitrate and ferricyanide 1 oo.n 1 r .0 _ 90.9 90.9 



of potassium J ' ^ ~ 



Cobaltous nitrate and ferrocvanide 1 00 r o c^ o/^ o or n 



01 potassmm J 



Cobaltous nitrate and manoani- ) on 't . a o ia r ^1 a 



'^ >oy-7 + 0'b — 40'5 41'0 



cyanide of potassium 



} 



Apart from the mostly very slight secondary influence of the 

 chjinge of density, according to this the magnetism of the 

 binary compounds is directly composed of the magnetism of 

 their constituents. If the latter, without altering their con- 

 stitution or the grouping of their atoms, change into other 

 binary compounds, they still preserve the magnetism proper 

 to them. 



8. In general the molecular magnetism changes if the constitu- 

 tion of the conqwunds changes. — The most interesting example 

 of this kind is presented by the cupric salts, which are strongly 

 magnetic (as, for instance, cupric chloride and cuprio 

 bromide), while the cuprous salts and also metallic copper 

 are feebly diamagnetic. Therefore a dianiagnetic metal 

 (copper) comhined ivith diamagnetic eleinents {e.g. bromine) 

 may furnisli magnetic co7npoimds. The basis of these pheno- 

 mena is perhaps to be sought in the occurrence in intensity 

 of the molecular currents which condition diamagnetism in 

 the molecular groups of metallic copper — groups in them- 

 selves very feebly magnetic, but formed out of Avell conduct- 

 ing copper atoms, — while in the molecules of its salts those 

 currents do not meet with the copper atoms requisite to their 

 formation united in equal measure. 



We will subsequently produce further examples of altera- 

 tions of molecular magnetism with alteration of constitution. 



9. The magnetism of the hydrates of the magnetic metals 

 was determined according to the same method which served 



"to 



