﻿316 Intelligence and Miscellaneous Articles. 



particularly that of cupric bromide, a salt both whose constituents 

 (copper and bromine) are feebly but decidedly diamagnetic, as direct 

 determinations show. Two diamagnetic elements can thus by their 

 combination give a magnetic compound. 



That this magnetism of copper salts is to be ascribed to the copper 

 itself is proved by its constancy in various salts, even when, as in the 

 double cyanides, the magnetism of the simple or compound radical 

 united with it is changed. 



IV. In other investigations two solutions of .known magnetism, 

 M 1 and M 2 , which change their constituents by double decomposition, 

 were mixed in a glass and the magnetism M m of the mixture investi- 

 gated. Among others the following solutions were mixed : — 



Ferric chloride and potassium ferrocyanide .... 20*4 21*1 



Ferrous sulphate ,, ,, .... 41*2 40*3 



Cupric sulphate ,, ,, .... 07 08 



Nickel sulphate ,, „ 20*3 22'5 



Ferric chloride and potassium sulphocyanide .. 15*1 14*6 



Manganous sulphate and potassium ferrocyanide. 71*8 70'2 



The solid form in which one of the salts formed by double decom- 

 position is frequently precipitated exercises in only a few cases any 

 disturbing influence. 



Hence, if we mix two sails whose constituents change by double elec- 

 tive affinity, the total magnetism of the solutions is the same after 

 double decomposition as before. 



We can draw from this with great probability the following con- 

 clusion : — That the magnetism of a binary compound is made up by 

 simple addition of the magnetisms of both its constituents in their re- 

 spective conditions ; and that these constituents, when they enter into 

 other binary compounds without changing their constitution or atomic 

 grouping, retain their atomic magnetism without alteration. 



V. From the equality of the atomic magnetism of solid potassium 

 ferrous oxalate with the atomic magnetism of other ferrous salts, as 



well as of potassium ferric oxalate and of potassium iron alum in a solid 

 form with that of the other ferric salts, we can prove, in opposition to 

 the views based on the peculiar colour of the salts *, that in these salts 

 in the solid form the iron is contained in the same manner as in other 

 ferrous and ferric salts. The constancy of the atomic magnetism 

 proves that in the different coloured chromic salts the magnetic 

 atomic group retains its properties unchanged. It also remains un- 

 changed if anhydrous copper or nickel salts combine with water, an 

 observation which does not agree well with Graham's views on the 

 constitution of the ammoniacal copper salts. On the other hand, 

 luteocobaltic chloride and purpureocobaltic chloride are diamagnetic ; 

 so that, unlike the copper salts, they are not to be regarded as simple 

 cobaltic salts united with ammonia; the atomic group containing 

 the metal and determining the atomic magnetism must be es entially 

 different from what it is in the simple salts. 



* Compare Haidinger, Pogg. Ann, vol. xciv. p. 246. 



