8 CHEMISTRY. 
retort must be luted or cemented as closely as possible. The globes o1 
matrasses (jigs. 27, 28, and 29) are used for the purposes of receivers. In 
order that the neck of the retort may fit as accurately as possible into that of 
the globe, one of the latter is selected whose neck in one place is only a 
little wider than that of the retort to be set in it, and the neck of the 
globe broken off at this place with the help of a splitting iron (fig. 24). Of 
these irons there must be a considerable number at hand ; to use them, one 
is selected fitting the neck of the globe, or indeed any other cylinder of 
glass, at a given place. It is then to be heated red hot and brought to the 
place in question, being held there for a few seconds. On removing the 
ring and pouring cold water on the heated glass, this will crack off evenly at 
the part which had been surrounded by the red hot iron ring. Having cut 
off the neck of the receiver to the proper length (it may possibly not require 
the operation at all), the neck of the retort is inserted into it, and the joining 
well luted. To support the receiver at the proper height, we may use a 
small table, as represented in pl. 30, fig. 10. The stem of this can move 
up and down in the cylindrical part, a, of the stand, and may be fixed at any 
height by a screw. The retort thus placed in the sand bath, with the 
receiver supported by the table, and generally resting on a ring of some kind 
for greater steadiness, heat is to be applied under the furnace and the 
receiver kept constantly cooled. The vapor arising from the ebullition, and 
passing over into the receiver, is there condensed again into a liquid. 
For distillation on a larger scale we make use of the alembic. For this 
purpose the alembic is constructed in two different shapes. A very 
simple arrangement, and one long in use, is the small alembic represented 
in pl. 30, figs. 11 and 12. The vessel, 6, in fig. 11 is intended to contain 
the liquid to be distilled. This is closed above by a head, a, shown more 
fully in fig. 12, well fitted to the body, and the junction luted to prevent the 
escape of vapor. On heating the bottom of the body, b, the vapor of the 
boiling liquid ascends into the head, and passes through the neck into the 
receiver, which is kept constantly cool. By means of an aperture in the 
head, closed by a glass stopper, fresh material may be introduced into the 
body without interrupting the operation. 
A convenient arrangement for a distilling apparatus, which may be used 
for preparing distilled water, is shown in figs. 4 and 5. AB is the furnace 
over which the alembic, C, is heated. The part E fits exactly, with its 
under portion somewhat conical, into the opening of the alembic C 
(figs. 4 and 5); the head itself, D (fig. 5), has the following arrangement: 
‘The interior of the cylinder E, which is in connexion with the space of the 
alembic and receives the vapor, is closed like a roof above, as seen in fig. 5. 
At the base of this roof is the escape-pipe. The space D is filled with cold 
water. On bringing the water in the alembic, C, to boil, the steam ascends 
to the roof over F, and is here condensed by contact with the constantly 
cold walls, escaping by the pipe in the liquid form. In this arrangement 
the head itself forms the cooling apparatus. 
A complete distilling apparatus, with a very convenient arrangement for 
cooling the vapors, is shown in pl. 31, fig. 3. A is an alembic, generally 
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