212 Richard Adie, Esq., on the Connection between the 



yet it gives the dark-coloured oxide and sulphuret, both of which are 

 strongly magnetic ; for if well dried specimens are strewed on a sheet 

 of paper, some of their particles are moved after the manner de- 

 scribed, but not enough so as to allow the powder to be streaked like 

 the sulphuret of arsenic. The diniodide of copper is a pale-coloured 

 substance, more magnetic than copper, but not sufficient to move in 

 the least degree on paper ; when heated on silver it parts rapidly with 

 iodine and darkens in hue ; if the heat be continued till the iodine is 

 nearly all exchanged for oxygen, the dark-coloured body left moves 

 as freely, if not more so, on paper, than the pure black oxide. A 

 result similar to this I have also obtained, where the oxide of copper 

 had been digested in hydrofluoric acid, then heated with a flux to 

 600, and \h<Q insoluble dark-coloured residue washed out to be tested. 



L,ead and Tin. — These metals possess more magnetism on the 

 torsion balance than many of the white-coloured substances they 

 enter into. Their coloured oxides and sulphurets are more magnetic 

 than the metals, but inferior to the similar compounds of the other 

 metals already noticed. The pure white fluoride of lead is the least 

 magnetic of the metallic fluorides ; when fused, it passes to a light 

 greyish brown, and gains in attractive force. In this powder there 

 are a few darker-coloured particles that move readily to the magnet 

 on paper. The colourless acetate of lead is repelled by the magnet ; 

 decomposed by heat it yields a dark-coloured carburet sufficiently 

 magnetic to move slightly on paper to a magnet underneath. The 

 fine yellow-coloured chromate of lead is nearly quite inert before the 

 magnet ; fused brown, it becomes nearly equal to the carburet of lead 

 in attractive force. 



Bismuth, Antimony, and Zinc, in their pure state, have been 

 shewn by Dr Faraday to belong to the class of diamagnetic bodies ; 

 in union with oxygen or fluorine they give light-coloured substances 

 decidedly magnetic by the torsion balance, which would indicate that 

 these metals are magnetic to a considerable degree, but that the 

 magnetism is masked by some force, most probably connected with 

 their crystallization. This supposition led me to a long tedious 

 search among the compounds of these metals for bodies that would 

 exhibit their attraction when spread on paper. Ultimately I found 

 that partially-reduced or sub-oxides could be prepared in a simple 

 manner, possessed of strong attraction, and all of them darker in 

 colour than the oxide from which they had been derived. In their 

 preparation the colour is a guide to the success or failure of the 

 process ; for if the heat is carried too far, the reduced portion is re- 

 oxidized, the colour is too light, and the magnetic property is lost. 

 Bismuth is the most diamagnetic of the elementary bodies — the light- 

 coloured oxide is attracted on the torsion balance when heated with 

 a flux composed of equal parts of borax and citric acid crystals 

 bruised, a mixture is washed out from the residue, or even in the 

 unwashed residue pulverised there are particles which move with the 



