V 
OBSERVATIONS. 8 1 
ioo parts of iron, diffolved in marine 
acid, muft then precipitate from it- 
felf fo much iron as is equivalent to 
854- parts of iron in a metallic ftate, or 
120 parts of calx of iron phlogifticated 
by heating and attradlable by the mag¬ 
net. • 
According to thefe experiments, the 
quantity of iron in a ftate of phlogifti¬ 
cated calx contained in one ounce of 
foap-rock is 3 44. grains, 
§ 4 4 
The earths of the folution were preci¬ 
pitated by cryftallized fixed vegetable al¬ 
kali, and, when edulcorated and calcined, 
weighed 192 grains. A proper quantity 
of diftilled vinegar, fomewhat concen¬ 
trated by froft, was added to this preci¬ 
pitate, and after digeftion the folution 
was filtred. The earth remaining upon 
the filtre was dried again, and calcined, 
G and 
% 
