120 
METALLIC OXIDES. 
Oxides of tin. the solution is not altered neither by boiling, nor by the addi- 
tion of a great quantity of concentrated muriatic acid, nor by 
that of water. 
"When I precipitated a solution of the spirit of libavius by 
the caustic ammonia, the preceding phenomena took place 
again — that is to say, when I poured water fot a second time 
on the precipitate, it was softened, and began to pass through 
the paper filter with the water. The lactescent liquor which 
passed through the paper, was again precipitated by the addition 
of more ammonia. On being evaporated, it yielded a yellow- 
ish jelly, which dissolved in cold as well as boiling water, and 
was also soluble in the acids. The oxide containing the alkali, 
when dried at a moderate temperature, is colourless, transpa- 
rent, and soluble in the acids. Dried at a more elevated tem- 
perature it lost its solubility in acids 5 probably in consequence 
of an ulterior oxidation. The same thing took place when 
it was heated to a red heat : it then became, in proportion as the 
heat increased, yellow and orange, and lastly a very deep red, 
like cinnabar ; but as it cooled, these colours disappeared in 
an inverse order, and the oxide only preserved the pale yellow 
cf the citron. The properties which form the distinguishing 
characters of this degree of oxidation are, to afford a very 
volatile salt with muriatic acid ; and this salt is not decomposed 
either in boiling water, nor by the addition of concentrated mu- 
riatic acid, nor by the salts of gold or copper. 
Yellow Oxide of Tin. 
The oxide which is obtained by the action of nitric acid upon 
tin, is white, and preserves, as I have remarked in another 
place, although it may have been washed in the most careful 
manner, the property of giving a red colour to turnsole. Du- 
ring the drying, it became nearly transparent, yellow, and hard $ 
on exposure to fire, it lost the water, and, at an elevated tem- 
perature, assumed a deep brown colour, which, after refrigera- 
tion, remained only a yellow : and on being pulverized, almost 
entirely disappeared. 
A portion of the oxide of tin, obtained by the nitric acid, 
carefully washed, but not dried, was digested with concentrated 
muriatic acid in a boiile well stopped. The acid assumed a 
yellowish 
