OBSERVATIONS. 39 
* ' 
This mixed and melted in a ftrong fire 
during an hour, in a crucible lined with 
charcoal, and to which a cover was lu¬ 
ted, (as has been done in all the following 
experiments,) gave a dirty olive coloured 
fcoria, in which the reduced globules of 
tin lay difperfed ; thefe were collected by 
powdering and wafhing, and weighed 10 
grains and a half. 
(b) As I had often found the fal fedati- 
vum to be a remarkably good flux for re¬ 
ducing metals, I tried it in this inftance, 
and mixed 
Wood-tin, 1 dram. 
Sal fedativum, 3 drams. 
Powdered charcoal, io grains. 
This mixture, melted like wife during an 
hour, gave a blackifh lamellar porous 
fcoria, mixed with charcoal: the tin glo¬ 
bules contained in it, feparated by pow¬ 
dering and wafhing, weighed 19 grains. 
(c) I was led to fuppofe an hour to be 
too long for keeping it in a melting ftate, 
D 4 becaufe 
