METALLIC OXIDES. 
1 25 
The following experiments put it beyond doubt, that these two Oxides of tin, 
oxides have not the same degree of oxidation. 
A solution of the spirit of libavius in water, was precipitated 
by the carbonate of potash, and the precipitate washed with 
cold water. On pouring cold water a second time upon it, 
it melted like butter on the fibre, and a liquor which had a 
milky appearance, passed through the paper, and was preci- 
pitated afresh when it fell into the alkaline liquor, which was 
already filtrated. After the space of 24 hours, it became 
clear, and was of a pale yellow colour; it had an alkaline taste, 
notwithstanding, it was precipitated afresh by the addition of 
alkali. The nitric acid, as well as the muriatic acid, produced 
a precipitate, which, nevertheless, was dissolved by an addition 
of acid in excess. The solution made by the muriatic acid, 
was not altered by ebullition, but that which was made in the 
nitric acid, formed a jelly a little time before it arrived at the 
temperature of 100°. 
Another portion of this oxide on which coid water had been 
poured but once, was dried by being pressed between thick folds 
of blotting paper, and the drying was at last accomplished, by 
exposing it, in a temperate place, to a current of air. The oxide 
then took the form of little colourless pieces, some transparent, 
and resembling pulverized glass. It comported itself with the 
acids in the following manner : 
In sulphuric acid , diluted with an equal quantity of water, 
a great part dissolved, but when a large quantity of acid was 
used, it was totally dissolved. When the oxide before being 
perfectly dry was treated with the sulphuric acid, much diluted 
with water, it lost its transparency, and fell in a powder, and 
produced a soluble super-sulphate, and an insoluble sub-sul- 
phate. 
Nitric Acid has the property of dissolving this oxide until 
its acid taste is replaced by an astringent one. The saturated 
nitric solution becomes gradually turbid, and, on being exposed 
to an elevated temperature, it coagulates, loses its astringent 
taste, and becomes acid again. I have not been able to per- 
ceive, that, on this occasion, any of the nitric oxide gas (ni- 
trous gas) is disengaged, probably because the acid is only re- 
duced to nitrous.acid. 
i Muriatic Acid softens it at first, and at last dissolves it ; and 
the 
