456 TESTING FOR ANTIMONY AND ARSENIC. 
residue, by the addition of hydrochloric acid, and to this 
hydrochloric solution water was added, which caused a bulky 
white precipitate — the sub-chloride of antimony; but the 
liquor contained some copper, which was evident from the 
colour of it ; and, therefore, I separated the white precipitate 
from the liquor, and washed it well, to free it as perfectly as 
practicable from the liquor. I then dissolved the white pre- 
cipitate by the addition of solution of tartaric acid, and passed 
sulphuretted hydrogen gas through the solution, whereby a 
precipitate of sulphuret of antimony, of a tolerably pure 
orange-red colour, was obtained. These several results gave 
full, satisfactory proof that the coating which cracked off 
from the copper contained antimony. I also passed sulphu- 
retted hydrogen gas through the solution, or liquor separated 
from the white precipitate, and a nearly black precipitate of 
sulphuret of copper was obtained. This sulphuret of copper 
appeared to be nearly as much as the orange sulphuret of 
antimony ; from w hich I concluded that only about one-half 
of the quarter of a grain of the coating might be antimony ; 
but the quarter of a grain was only about one-half of the coat- 
ing on the w 7 hole of the tw 7 enty-two inches of copper. 
After the twenty-two inches of copper had been removed 
from the solution of the 7 555 grains of liver, I immersed three 
other pieces of copper in the same hot solution, consecutively, 
for four hours. In each instance I got a coating upon the 
copper, strong upon the first of the three pieces, and weak 
upon the last. From their appearance, I concluded that 
there could not be less than another quarter of a grain of anti- 
mony deposited on them ; and I believed that from the w hole 
of the 7 555 grains of liver I had separated half a grain of 
antimony, making the total in the whole liver (which weighed 
four pounds) about T85 grains, equal to rather more than 4*9 
grains — say to 5 grains — of tartar emetic. 
The orange sulphuret of antimony, obtained as mentioned, 
w r as dried, and then dissolved by heating it in strong hydro- 
chloric acid. I introduced the solution, along with diluted 
sulphuric acid and zinc, into Marsh’s apparatus ; and the 
flame of the gas produced gave deposits of metallic anti- 
mony upon a Wedgewmod’s ware pestle applied to it ; which 
deposits did not dissolve with strong solution of chloride 
of lime. 
In another experiment, in a solution of about one-eighth of 
the whole liver in diluted hydrochloric acid, I immersed a 
piece of pure zinc (after having further diluted the solution 
with water so much as to make it act but feebly on the zinc), 
and kept it in the solution for four days, at the expiration of 
