ACTION OF MAGNETS ON METALS AND THEIR COMPOUNDS. 47 
2375. Chromate of lead, when subjected to the magnet, pointed equatorially and 
was repelled. Such was the case also with crystals of the chromate of potassa. 
Crystals of the bichromate, however, did not act thus ; for if in any way affected 
they were in the least degree magnetic, showing the influence of the increased pro- 
portion of chromic acid. Solutions of either salt pointed well equatorially and were 
repelled ; thus showing the diamagnetic influence of the water present (2422.). 
2376. As just stated, a solution of the bichromate contained in a tube, pointed 
equatorially and was repelled ; but if the same solution had a little alcohol added to 
it, and also some pure muriatic or sulphuric acid, and were then heated for a few 
minutes to reduce the chromic acid to the state of oxide or chloride, then, on being 
returned to the tube and subjected to the magnet, it was found strongly magnetic. 
2377. I think it has before been said that chromium is a magnetic metal ; as these 
results have been obtained with its pure compounds, there is no longer any doubt on 
my mind that such is the case. 
2378. Lead. — The compounds of lead point equatorially and are repelled. The 
substances tried were the chloride, iodide, sulphuret, nitrate, sulphate, phosphate, 
carbonate, protoxide fused, and the acetate. A portion of very carefully crystallized 
nitrate being dissolved was precipitated by pure zinc, and the lead obtained washed 
with dilute nitric acid, to remove subsalts. Such lead was free from magnetism, and 
therefore the metal ranks in the diamagnetic class, both directly and by its com- 
pounds. Lead usually appears to be magnetic, and it is not very easy to obtain the 
metal in the pure diamagnetic state. 
2379. Platinum. — I have, as yet, found no wrought specimens of this metal free 
from magnetism, not even those prepared by Dr. Wollaston himself, and left with 
the Royal Society. Specimens of the purest platinum obtained from Mr. Johnson 
were also found to be slightly magnetic. 
2380. Clean platinum foil and cuttings were dissolved in pure nitro-muriatic acid, 
and the solution evaporated to dryness. Both the solution and the dry chloride 
pointed equatorially and were repelled by the magnet. A part of the chloride being 
dissolved and rendered acid, was precipitated by an acid solution of muriate of am- 
monia, and the ammonio-chloride of platinum washed and dried : it also, at the 
magnet, pointed equatorially and was repelled. A portion of this ammonio-chloride, 
decomposed in a flint-glass tube by heat, gave spongy platinum, which being pressed 
together into a cake, pointed axially and was attracted at the side of the magnetic 
pole, being magnetic. 
2381. At present I believe that platinum is as a metal magnetic, though very 
slightly so ; and that in the compounds, the change of state and the presence of other 
substances having the diamagnetic character, are sufficient to cover this property and 
make the whole compound diamagnetic (2422.). 
2382. Palladium. -All the palladium in the possession of the Royal Society, pre- 
pared by Dr. Wollaston, amounting to ten ingots and rolled plates, is magnetic. 
