METALLIC OXIDES, 
16 1 
©f umber. At a very high temperature it becomes an azure Oxides of tin, 
blue, and when pulverized, does not lose its colour. 
In the nitrate of copper, it gave a greenish white precipitate, 
which, after drying, had a vitreous fracture, and was of a satu- 
rated green colour. When at a red heat, it became black, and 
gave to paper a greenish umber colour. 
In the sulphate of manganese, this v/hite precipitate turns 
brown when in contact with the air. ♦ 
In the ferreous sulphate, it gave a white precipitate which in 
contact with the air, assumed all the colours belonging to the 
oxides of iron, and terminates by becoming a vitreous mass, of 
a deep brown colour, from which the oxide of iron cannot be 
extracted, except to a certain degree, by the muriatic acid. 
.By dissolving impure tin in the nitro-muriatic acid, this same 
combination is obtained, which is precipitated during the eva- 
poration of the acid, in the form of a blueish green powder, and 
which, after being exposed for some days to the access of the 
air, assumes a dark rusty colour. 
In the hydrargric muriate, (corrdsive sublimate) it gives a 
yellow precipitate, which, after some moments, becomes red— 
when well washed, it turned carnation, and, after being dried, 
it was of a brown colour, and appeared to be a triple combina- 
tion. 
In a solution of the muriate of ammonia, it gave a white 
precipitate, soluble by the addition of a certain quantity of 
water — and this solution was easily precipitated by adding am- 
monia. The precipitate collected on the filtre' is readily dis- 
solved in water, after the alkaline liquor has been drained off. 
This solution, left in an open vessel, becomes, after a few days, 
less fluid, and nearly like a saturated solution of gum arabic, 
without losing any of its transparency. I attribute this to a 
commencement of deposition of the oxide. 
A solution of the oxide of tin in a diluted lixivium of caustic 
kali being left in a closed phial, was decomposed by degrees, 
the oxide was precipitated, and the fluid remained like a jelly. 
This jelly, on being shaken a little, became liquid, and the 
oxide passed through the fibre — if they are to be separated, it 
requires some days for the jelly to set again. 
These experiments prove, that the oxide of tin, although it 
possesses some of the properties of an acid, has nevertheless so 
Vol, XXXV.— No. m, M weak 
