W W. sturgeon, Esq., on the 



copper, platinum, tin, antimony, lead, zinc, bismuth, and mer- 

 cury ; and also some of their alloys and salts. In none of 

 these metals, when in a state of purity, have I been able to 

 discover the slightest trace of magnetic action, though in se- 

 veral specimens of some of them, as they appear in a com- 

 mercial state, magnetic action is strongly developed. 



18. A bar of bismuth, for instance, cast from a mass fused 

 in an earthenware crucible, was found to be highly magnetic, 

 and, for a while, was considered as a good specimen of the 

 magnetic action of that metal ; but on examining another bar 

 cast from the remaining portion in the crucible, and finding 

 it still more powerfully magnetic than the former, a suspi- 

 cion was aroused that either their crystalline structures were 

 different to each other, or that the metal was not pure. The 

 experimental inquiries which this suspicion occasioned, led 

 to the detection of localities in the two bars in which the 

 magnetic actions were more powerful than in the other parts 

 of them, which gave rise to the determination of sweating one 

 of the bars at a low heat, and running out of the crucible the 

 most easily fused portions, before the rest became fluid, which 

 is an excellent process for freeing pure bismuth from some 

 of the impurities with which it is frequently contaminated in 

 the mercantile state. 



19. This purified bismuth having been cast into a bar, was 

 afterwards broken into convenient fragments, and tested by 

 the Torsion Magnetoscope, previously described (16) ; but not 

 the slightest trace of magnetism could be detected in any of 

 the pieces. 



20. Having satisfied myself that no magnetic action re- 

 sided in the pure bismuth, the dross left in the crucible was 

 softened by heat, and poured on a stone slab, and on being 

 tested developed highly magnetic powers. It now became 

 obvious that the whole of the magnetism displayed by the 

 bismuth, when in its first state (17), was due to that portion 

 only which was left as dross in the crucible after the pure 

 metal had been run out. 



21. From the results thus arrived at, I was induced to fuse 

 other portions of mercantile bismuth, and run out the purest 

 portions of the metal at the lowest degree of fusible heat, by 



