OBSERVATIONS. 73 
: '■ 1.. ' ^ ; ' 
it, and whofe merit in chemiftry is fo 
well known. However, what Mr. Scheele 
affirms, that this acid of wolfram or tung- 
ilen is foluble in 20 times its weight of 
water, is true only when the acid of 
wolfram is ftill moift j for if it is in a 
ilate of dry powder, fcarcely 150 times 
its weight of water are fufficient to dif- 
folve it. This acid is not ftrong, having 
more of a difagreeable metallic than four 
tafte. Its folution in water is very little 
altered by the phlogifticated alkali, but 
does form after fome time a little white 
precipitate. With lime-water and the 
folutions of calcareous and ponderous 
earth in marine acid, it forms an opal 
colour, and a white precipitate. The fo¬ 
lutions of copper and iron are not altered 
by it } but filver, mercury, and tin, are 
precipitated white by it from their folu¬ 
tions. The precipitate of tin fhews af- 
% 
ter fome time a bluiffi green colour: 
If the dry acid of wolfram be employed, 
fhe folution of tin in marine acid is ren¬ 
dered 
