LABORATORY. 
ratus. A is the retort fitted by grinding 
into a plug or piece, B, represented at b, 
which last is also fitted by grinding into the 
neck of a globular receiver, C. 
The use of the additional piece, b, is to 
afford a due inclination to the retort by an 
obliquity of its perforation or hole, instead 
of allowing it to remain horizontal, as it 
would, if fitted to the hole in C, and also 
to facilitate the grinding in, of a new re- 
tort in the case of breakage. The piece, 6, 
has a stopper, a, which can be put when- 
ever the retort is taken out, whether for 
weighing at, or for any other purpose. The 
first receiver, C, has a smaller neck oppo- 
site to B, which is ground into a corres- 
ponding neck of D, the second receiver, 
which last is tubulated, and has a tube, 
H, open at both ends, ground into its 
vertical neck for the purpose of permitting 
absorption and re-acting, by its contents, 
against the force required to protrude any 
gas through the bended tube, I K L. 
Every one of the range of the receiver, E 
F G, has also two necks, by which they 
are successivelj^fitted to each other, and 
each interior neck has a tube of about a 
quarter of an inch fitted into it, which, by 
its curvate, reaches nearly to the bottom of 
the liquid (usually water) placed in each. 
By this disposition the- usual first product 
of condensation is received in C, and the 
purer vapours proceeding to D, are in part 
condensed by the water placed therein, 
and are partly urged through the tube, I, 
into contact with the water in E : and what- 
ever may escape condensation in E, will be 
urged through the tube, K, into the liquid 
in F ; and in this manner the operation 
may proceed through the whole set of ves- 
sels, till the gasiform remaining product, if 
any, shall pass out then beneath the mouth 
of one or the other of the three inverted bot- 
tles, at P, which are filled with water, and 
have their mouths immersed below tlie sur- 
face of the water, in a dish at the end of the 
series. S and s are a pair of pieces of wood 
which serve to support one of the globes, and 
very conveniently afford an adjustment, by 
pressing them more or less near together. 
Tills apparatus is drawn upon a scale of 
about half an inch to a foot, which is a pro- 
per size to be worked by an Argand’s 
lamp ; if it were made larger, the retort 
would of course require to be supported as 
usual, by the parts of the furnace, or other- 
wise. 
The dish and bottles at the extremity of 
this apparatus show how the gases or perma- 
nently elastic fluids are received and ma* 
naged. For such gases as are not absorbed 
by water, a wooden tub may be used, hav- 
ing a shelf therein, at such a depth as to 
stand a little below the intended surface of 
the water ; or, instead of a shelf, a short- 
legged stool, loaded with lead, may be 
used, and in that case any tub or vessel 
may be used. Jars, or vessels of any con- 
venient figure, being filled with water by 
immersion, and turning them bottom up- 
wards, may be placed on the shelf, which 
should have holes in it for the convenience 
of pouring up any gas, whether from ano- 
ther jar, bottle, or vessel, or from the neck 
or tube of a retort, or other apparatus. 
Jars, &c. thus filled may be conveyed away, 
either by corking the bottle, or by putting 
a saucer, or other shallow vessel, beneath 
the mouth of the jar, and taking both out to- 
gether, with water in the saucer. 
Gases which are absorbed by water are 
usually received over mercury, in which 
case, on account of the weight, as well as 
the expence of the fluid, the vessels are 
made smaller, and the trough has a deep 
cavity sufficient for immersion, but no 
larger, and a broad shallow part of the 
trough supplies the place of a shelf for the 
jars to stand upon ; and there is an actual 
shelf at one part only over the end of the 
deep cavity. Fig. 6, represents a trough for 
mercury, which may be made of wood or 
of stone. The space, V, admits the jar. A, to 
be immersed, and when full it is raised and 
placed bottom downwards upon the shallow 
bottom. G is a retort, containing some 
materials from which gas, being extricated, 
rises beneath A, and displaces the mercury. 
X and Y are grooves, into which one or 
more wooden shelves may be slided, as 
occasion may require, in which application 
they are first introduced at the wider part, 
T, in the plan, tig. 7. 
An apparatus, almost indispensable in ex- 
periments on the gases, is a gazometer, 
which enables the operator to receive and 
preserve large quantities of gas with the 
aid of only a few pounds of water'. These 
vessels are made of various forms, but one 
of the most simple is shown in fig. 8. It 
consists of an outer fixed vessel, d, and an in- 
ner moveable one, c, both of japanned iron. 
The latter slides easily up and down within 
the other, and is suspended by cords pass- 
ing pnllies, to which are attached the coun- 
terpoises, &c. To avoid the incumbrance 
of a great weight of water, the outer vessel, 
d, is made double, or is conrposed of two 
