piiaHmacy, 
and tlien is conveyed away to be con- 
densed. The vessel most commonly em- 
ployed for this purpose is llie common cop- 
per still, which consists of a body for con- 
taining the materials, and a head into ’which 
the vapour ascends. From tlie middle of 
the head a tube rises for a short way, and 
is then reflected downwards, through which 
the steam passes to be condensed. Another 
kind of head, rising to a great height before 
it is reflected, is sometimes used for sepa- 
rating fluids, which differ Tittle in volatility, 
as it was supposed that the less volatile va- 
pours would be condensed and fall back 
into the still, while only the more vola- 
tile vapours would arise to the top, so as 
to pass to the refrigeratory. The same ob- 
ject may be more conveniently attained by 
managing the fire with caution and address. 
The greater the surface exposed, and the 
less the height the vapours have to ascend, 
tlie more rapidly does the distillation pro- 
ceed ; and so well are these principles un- 
derstood by the Scotch distillers, that they 
do not take more than three minutes to dis- 
charge a still containing gallons of fluid. 
The condensing apparatus used with the 
common still is very simple. The tube in 
which the head terminates is inserted into 
the upper end of a pipe, which is kept cool 
by passing through a vessel filled with 
water, called the refrigeratory. This pipe 
is commonly made of a serpentine form ; 
but as this renders it difficult to be cleaned, 
T)r. Black recommends a sigmoid pipe. 
The refrigeratory may be furnished with a 
stop-cOck, that when the water it contains 
becomes too hot, and does not condense all 
the vapour produced, it may be changed 
for cold water. From the low er end of the 
pipe, the product of the distillation drops 
into the vessel destined to receive it; and 
we may observe, that when any vapour 
issues along with it, we should either dimi- 
nish the pow'er of the fire, or change the 
water in the refrigeratory. There was a 
process of this kind, called circulation. It 
consisted in arranging the apparatus, so 
that the vapours were no sooner condensed 
into a fluid form, than this fluid returned 
back into tlie distilling vessels, to be again 
vaporised ; and was effected by distilling in 
a glass vessel, with so long a neck that the 
vapours were condensed before they escap- 
ed at tlie upper extremity, or by inverting 
one matrass within another. When corrosive 
sutjstances are distilled in this way, the 
cucurbit awl alembic are used ; but tliese 
substances are more conveniently distilled 
perlafns. 
Tlie distillation per latufi is perfonrieef iff 
a retort, or pear-shaped vessel, having the 
neck bent to one side. The body of a 
good retort is well rounded, uniform in its 
appearance, and of an equal thickness, and 
the neck is sufficiently bent to allow the 
vapours, when condensed, to rim freely 
away, but not so much as to render the 
application of the receiver inconvenient, or 
to bring it too near the furnace. The pas- 
sage from the body into the neck must be 
perfectly free and sufficiently wide, other- 
wise the vapours produced in the retort 
only circulate in its body without passing 
over into the receiver. For introducing 
liquors into the retort without soiling its 
neck, which would injure the product, a 
bent funnel is necessary.- It must be suffi- 
ciently long to introduce the liquor directly 
into tlie body of the retort ; and in with- 
drawing it, we must carefnlly keep it ap- 
plied to the upper part of the retort, that 
the drop hanging from it may not touch the 
inside of the neck. In some cases, where a 
mixture of different substances is to be dis- 
tilled, it is convenient and necessary to have 
the whole apparatus properly adjusted be- 
fore the mixture is made, and we must 
therefore employ a tubulated retort, or a 
retort furnished with an aperture, accurate- 
ly closed with a ground stopper. This 
tnbu'lature should be placed on the upper 
convex part of the retort before it bends 
to form the neck, so that a fluid poured 
through it may fall directly into the body 
1 without soiling the neck. 
Retorts are made of various materials. 
Flint-glass is commonly used when the 
heat is not so great as to melt it. For dis- 
tillations which require excessive degrees 
of heat, retorts of earthenware, or coated 
glass retorts are employed. Quicksilver is 
distilled in iron retorts. 
The simplest condensing apparatus used 
with the retort, is the common glass re- 
ceiver ; which is a' vessel of a conical or 
globular form, having a neck sufficiently 
wide to admit of the neck of the retort be- 
ing introduced within it. To prevent the 
loss and dissipation of the vapours to be 
cor. 'ensed, the retort and receiver may be 
accurately ground to each otlier, or secured 
by some proper lute. To prevent the re- 
ceiver from being heated by the caloric 
evolved during the condensation of vapours’ 
in it, we must employ some means to keep 
St cool. It is either immersed in cold Water, 
or covered with snow, or pounded ice, or a’ 
constant evaporation is supported from Us 
surface,- by coveriug it with a cloth, wiiielv 
