SEPARATION OP ARSENIC. 
309 
inch in its internal diameter. It is bent into the form of a 
syphon, the shorter leg being about five inches, and the longer 
about eight inches in length. A stopcock ending in a jet of 
fine bore, passes tightly through a hole made in the axis of a 
soft and sound cork, which fits air-tight into the opening of 
the lower bend of the tube, and may be further secured if re- 
quisite, by a little common turpentine lute. To fix the appa- 
ratus, when in use, in an upright position, a hole is made in 
a wooden block for the reception of the lower part of a pillar, 
and a groove is cut in the top of the same block to receive the 
bend of the tube. Two elastic slips cut from the neck of a 
common bottle of India rubber, keep the tube firm in its 
place. 
The matter to be submitted to examination, and supposed 
to contain arsenic, if not in the fluid state, such as pastry, pud- 
ding, or bread, &c, must be boiled with two or three fluid 
ounces of clean water, for a sufficient length of time. 
The mixture so obtained must then be thrown on a filter to 
separate the more solid parts: thick soup, or the contents of 
the stomach, may be diluted with water and also filtered; but 
water-gruel, wine, spirits, or any kind of malt liquor and such 
like, or tea, coffee, cocoa, &c, can be operated on without any 
previous process. 
When the apparatus is to be used, a bit of glass rod, about 
an inch long, is to be dropped into the shorter leg, and this is 
to be followed by a piece of clean sheet zinc, about an inch and 
a half long and half an inch wide, bent double, so that it will 
run down the tube till it is stopped by the piece of glass rod 
first put in. The stopcock and jet are now to be inserted, and 
the handle is to be turned so as to leave the cock open. The 
fluid to be examined, having been previously mixed with 
from a drachm and a half to three drachms of dilute sulphuric 
acid (1 acid and 7 water,) is to be poured into the long leg, 
till it stands in the short one about a quarter of an inch below 
the bottom of the cork. Bubbles of gas will soon be seen to rise 
from the zinc, which are pure hydrogen if no arsenic be pre- 
sent; but, if the liquor holds arsenic in any form in solution, 
