5-38 
M A TERI A 
glafs-blower’s lamp and bellows will be of eflential iervice 
for fenlir.g and bending glafs-tubes, and other purpofes. 
Some of thefe may appear unnecefljry, efpecially in large 
towns, where the different artifrs may be found ; but it 
will be ftrongly in the recolleftion of all who have had 
occafion to get apparatus made, that they can feldom get 
them con(huffed to their wifi), although they ftand bv the 
artift. The want of proper tools, and a little mechanical 
dexterity, have frequently prevented or put an end to ex¬ 
perimental invefligations of confiderable importance. 
Independent of the apartment containing the mechani¬ 
cal apparatus, the chemilt w ill require at leaf! one diliinfl 
room for a laboratory. Two rooms, however, fhould be 
employed when it is convenient. The principal room of 
the laboratory fhould be on a ground floor, for feveral rea- 
fons. A furnace for great heat fhould be in a low room, 
in order to hav-e the greateft length of chimney. The afn- 
pit of this furnace fhould terminate in a cellar under the 
laboratory, in order that the air may enter perpendicularly, 
and of the lowed poflible temperature. That fide of the 
laboratory allotted for furnaces fhould have an arch pro- 
jeffing into the room about three orfour feet, and of Inch 
height that a perfon may, freely walk under it. In the 
higheft pait of this arched portion mult be an opening 
into a chimney diftincl from the relf, and built up in the 
fame flack. It will be found more convenient to ufe port¬ 
able furnaces for moll purpofes, having none fixed but for 
producing very great heats, upon a larger fcale, and what 
are generally denominated melting furnaces. The iron 
chimney of the portable air-furnace may be carried to any 
height, and placed under or within the chimney ufed for 
the efcape of fmoke and vapours. 
On another fide of the laboratory fhould beplaced a ftone 
trough or fink, joined to a tub or cittern of water, which 
can be filled and emptied at pleafure, by means of a (top- 
cock over it, and a plug in the bottom. Over the fmk- 
flone fhould be fufpended a rack for holding bottles and 
glalTes to drain after waffling. On the fame fide may be 
placed a large block of wood or (tone, for the purpofe of 
holding a mortar or anvil occafiGiially. A third fide of 
this room may be occupied by cupboards and (helves, for 
holding the different apparatus of glafs and earthen ware, 
and for the different fubftances hereafter to be mentioned. 
The fourth fide, which fhould be the lighted, mufl be pro¬ 
vided with a table the w hole length of this fide, in the 
front of which, down to the floor, fhould be a number of 
drawers for holding all the dry fubftances. This table is 
for making the experiments upon, and for holding the ap¬ 
paratus in ufe at any time. 
If poffi.ble, every laboratory fhould be joined toafecond 
room, however fmall it may be, in which to perform the 
very nice and delicate experiments, and for keeping a few' 
books, and choice inftruments of metal, fuch as balances. 
See. This room fhould be kept very clean and dry, and 
as free as ponible from fleam and the fumes of acids. 
If any part of the furniture require to he painted, the 
paint fhould be made with fulpliat of lead, fince it is not 
acted upon by acids. This fubftance has been ufed, by 
Dr. Henry not only for this purpofe, but for repairing 
bioken glafs, and for labelling bottles. The following are 
the mofl particular articles with w hich a laboratory fhould 
be furnilhed. 
Mortars —Thefe are of various kinds, caft-iron, bronze, 
fleet, and WedgevvoOd-wnre. The caft-iron mortar is ge¬ 
nerally ufed tor vegetable fubftances, and f uch as are not 
liable to grim! off the iron. The hardnefs of this inftru- 
ment is much inercafed by calling the interior furface upon 
a metal mould, of the greater weight the better. The 
hardnefs of the bronze mortar, which is generally ufed for 
the fame purpofes, may be inercafed by the fame means. 
The fled mortar is ufed for reducing very hard minerals 
into fmall bits, fitted for grinding in the mortar of agate. 
It con-fills of a cylinder of hardened (led, with a flat bot¬ 
tom, and a peltle of the fame made to fit the mortar, accu¬ 
rately, from top to bottom. It is ufed by putting.the 
pieces of the mineral into it, and ftriking tiie peflle with 
C H EMIC A. 
a hammer. By this means it can be reduced Into toler¬ 
ably fmall particles, without grinding off any portion of 
the mortar. Hardened fleel mortars of the common fhape 
would be of great ufe, but it would be difficult to harden 
fo large a mafs without cracking. It might perhaps be 
made by welding a plate of calf fleel upon a thick piece 
of iron, and afterwards working it into the required fhape, 
and polifiring it in theinfide. If the fubftance is not very 
particular, it may be ground-in a mortar of YVedgewood- 
ware. If, on the contrary, it be very hard, the matter 
from the mortar will be liable to be mixed with the pow¬ 
der. In this cafe the agate mortar is much to be preferred} 
fome ftonesare, however, fo hard as to aft upon the agate. 
In tin is cafe, the matter to be ground fhould be weighed 
before and after grinding ; and the increafeof weight may 
be fafely deemed lilex, and allowed for in the analyfis ac¬ 
cordingly. 
Balance .—This inftrument is of great importance to the 
analytical chemift, and ought to weigh ioo grains to the 
■j^th of a grain. An account of the principles and con- 
ltruflion of the Balance will be found under that article, 
vol. ii. (See alfo. the article Chemistry, before referred 
to, at p. 386.) It will be almost unneceffary to obierve, 
that fo delicate an inftrument fhould be kept in a feparate 
apartment from the laboratory, where fumes of acids do 
not prevail. It fhould be clolely fhut up in a glafs cafe, 
having a Aiding door in the front. The firings to which 
the feales are fufpended fhould be of fine gold or filver 
cord, and the feales of filver or platina, and very thin. 
One of the feales fhould be provided with a loole pan of 
very thin platina, and balanced with the other, for the 
purpofe of holding the fubftance to be weighed. The 
weights for chemical fubftances fhould be reckoned in, 
and iharked with grains and decimals of grains. 
Lamp. —This valuable inftrument is a very great im¬ 
provement upon the land-bath. Its heat is regular, and 
may, by means of the concentric wick, be made of lulix- 
cient intenfity tor molt purpofes. Its greateft advantage, 
however, confifts in the facility with v\hich it can be ap¬ 
plied or withdrawn without lofs of time. For nice and 
delicate purpofes, where the heat of the lamp is required, 
alcohol, inftead of oil, gives an intenfe and Heady heat, and 
is not very expenfive when a proper veffel is ufed for burn¬ 
ing it. The latter kind of lamp is particularly adapted 
for a public lecture. 
The following articles of the materia ckemica it will be 
unneceffary to deferibe. 
Thermometers and a barometer. Bottle for afeertaining 
the fpecific gravity of liquids. 
A common ftill to furnifh diddled water; and a fmall 
one of filver for nice purpofes. 
The different blow-pipe apparatus; with platina, fpoon, 
ar.d leaf-platina. 
A filver crucible, and one of platina. 
Crucibles and crucible-ftands of earthen-ware. 
Muffels and cupels. 
Iron retort, and jointed tube, for procuring oxygen gas. 
Glafs jars of different fizes for collecting gafes. 
Filtering-paper, and papers coloured with litmus, tur¬ 
pentine, and red-cabbage. 
A general affortment of glaffes, to filter liquids into, See . 
An alfortment of earthen veffels for common purpofes. 
Thofe made of the fame, materials as the foda-water bot¬ 
tles are to be preferred. 
Capfules of glafs, and watch glaffes. The former may 
be cut out of broken retorts and receivers with a fmall 
hot iron. 
Glafs tubes of different fizes, and a fpirit-lamp for 
bending them. Glafs and porcelain rods and fpoons for 
(lining acids. Sec. 
jars of glafs and earthen ware, with grooves round the 
top, for luting them elofely from the air. Thefe fhould 
be ufed for containing falts in cryftals. 
Ruled paper for labels; copal varnilh to cover the/ame, 
to keep off thedumpnefs and fumes of acids. 
Sheets and wires of different metals. 
Silk 
