38 9 
may be analysed several ways* but that by means of hydra* 
sulphur of potash succeeds perfectly well, and is easy to prac* 
tise. 
Put in a sea-shell, or a tobacco-pipe, half a drachm of flour 
of sulphur, and a drachm of salt of tartar; combine them to¬ 
gether, by melting them over a strong fire, and then pour this 
mixture* into half a tea-cup full of boiling water. After it 
has settled, decant it clear into a bottle, and seal it hermeti¬ 
cally. it is well done, when it takes the colour and consistence 
of oil of olives. 
A few drops of this compound, poured into a glass of the 
liquor suspected of fraud, will show if there is any lead in it, 
and in what proportion. But, as this preparation also preci¬ 
pitates the particles of iron, it is sometimes important to draw 
a distinction between liquors impregnated with this latter 
metal, which has nothing unwholesome in it, and such as con¬ 
tain lead, copper, or arsenic ; the following receipt is practised 
with success : 
Fill a crucible with equal quantities of oyster shells, and 
brimstone in powder ; raise then the fire immediately by means 
of bellows, so as to keep the crucible to a white heat fora 
quarter of an hour; as soon as the mass has got cold, reduce it 
to powder, and put it in a vessel well stopped up. 
Whenever any of it will be wanted for use, put two drachms 
of vicam of tartar in a strong wine bottle; fill it with water, 
and make it boil for an hour; and then when it has got cold, 
stop it up, and shake it for some time. Afterwards, when it 
has settled, decant it clear into ounce vials, with twenty drops 
of muriatic acid in each, and then cork them well with wax 
and turpentine. 
A fourth part of this preparation poured out with three 
parts of the liquor to be analysed, will point out the least 
quantity of lead or copper by a black precipitate ; and of arse¬ 
nic by a yellow precipitate,but will have no effect upon iron. By 
saturating the precipitate with salt of tartar, if the liquor con¬ 
tains any of this latter metal, it will immediately turn black, 
but that which is pure will not change. Liquor, impregnated 
with particles of copper, will in a short time tinge polished 
steel with a yellow colour. A few drops of carbonate of am¬ 
monia will produce a fine blue. 
* As there are often pyrites, and always heterogeneous parts, in spring 
Water, it should be distilled, or else rain water is to be used. 
CC3 
CHAPTER 
