1819.] Dr. Vest on Vestium. 351 
hydrogen, water being now added, occasions no further alteration 
in the liquid. 
8. Caustic alkalies likewise precipitate vestium, and sulphur- 
etted hydrogen scarcely colours the precipitate ; but if an acid 
be poured in, the colour becomes brown. 
Y. A solution of common pure borax occasions no precipitate 
in diluted vestium solution ; but sulphuretted hydrogen throws 
down the vestium in that case likewise. 
As borax contains an excess of soda, I did not expect this 
result, and it is difficult to account for it. Probably the degree 
of concentration of the solution has an influence upon it. 
10. Tincture of nutgall throws down from the sulphuric and 
muriatic solutions of vestium a very small quantity of a white 
salt. From diluted nitric acid solution, it throws down nothing. 
11. Oxalate of potash throws down a copious white precipi- 
tate. 
12. The succinates trouble the solutions of vestium only 
feebly. 
13. The precipitate of vestium by sulphuretted hydrogen dis- 
solves with effervescence in nitric acid. 
14. Phosphate of soda throws down vestium white. 
15. A plate of zinc left for some days in a solution of vestium 
throws down white flocks. 
I conceive that the experiments here stated are sufficient to 
demonstrate, that a peculiar metallie¢ substance exists in the 
solutions. ‘The colourless solutions, the white salts, their solu- 
bility in water, the relation of these solutions to sulphuretted 
hydrogen and to ammonia, the white precipitates, the being 
thrown down by zinc—all these properties characterize this body 
as a peculiar metal differing from every other hitherto known. 
B.— Oxides. 
By rest and evaporation vestium yeaa itself from solu- 
tions, as we have seen, in white flocks, similar in appearance 
to fine mashed paper. Acids do not dissolve these flocks so 
easily as they do newly precipitated carbonate of vestium. I 
conclude from this, that vestium combines with two different 
doses of oxygen; for in the preceding respect, its properties 
resemble those of salts of iron and tin. 
It deserves attention that the oxides are distinguishable 
according to the medium in which they are formed. Lead, 
mercury, cobalt, and nickel, when they unite with acids, have 
obviously a different degree of oxidizement from that which 
exists in the oxides formed in the air, or when they unite with 
alkalies. The bodies with which they unite undoubtedly alter 
the proportion of their oxygen. ‘The oxides of mercury and lead 
are in salts undisputably white, and not coloured, as is the case 
with their oxides formed in the air. Cobalt must have a red 
oxide, as it gives that colour to acids, and this colour is, as we 
