OB SERVATIONS. 
35 
CHEMICAL EXPERIMENTS 
WOOD-TIN 
§ 1 
H E obftinacy to folvents which 
diftinguifties tin ores in general 
when examined in the liquid way, I have 
found in a great degree in the Wood-tin. 
(a) The fimple acids had very little 
effect. Aqua regia made a perceptible fo- 
lution : 60 grains of Wood-tin reduced to 
the moll fubtile powder, and digefted in 3 
ounces of it in a ftrong heat long conti¬ 
nued, loft only 5 grains, I tried there¬ 
fore the method recommended by Mr. 
Bergmann. 
(b) Upon two drams of finely powdered 
wood-tin, I poured one ounce of concen¬ 
trated acid of vitriol, and digefted it for 
D a fome 
