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110

or lube, that is beot ioto ahorizootal pofilioo

for which

reaCooIhis ioílrumeol is called a

re/orl:

is always of

ooe fiogle piece.

The mauer to be diílilled is iOlroduccd iOlo Ihe body

of Ihe retor! by meaos of a ladle wilh a loog lubular

Ibaok. Theo il is Cel io a faroace built purpoCely for

this uCe, aod

Ihal Ihe oeck of Ihe retor! comiog OUI

of Ihe furoace mRy, Iike Ihe Ihe ooCe

Ihe alembic,

{laod io a 1I0ping pofition, 10 facililale the egreCs of

tbe liquors, 'which by ils means are conveyed 10 a re·

ceiver, iOlo \Vhich it is iOlroduced, and wilh which it is

IUled. Tbis way

diíliJling, in which Ihe vapours

feemralher lO be driven out of the vell'e1 horizonlally

and lateraJly, Ihan raiCed up and fublimed, is

ror

that

reaCon caJled diílillation

pir lalul.

Retom are, of all the inílruments of diílillation,

1hoCe that muíl Cuílain Ihe greateíl heat, and refiíl Ihe

Ilrongell Colvenls

and therefore Ihey mul! nOI be mlde

gf melal. SJme, however,' which are made of iron may

do well enongh on cenain occafions: The ren are eilher

gf glafs or earrh. Thofe of glaCs, for the rearons aboye

given, are preferablelOIhe olher Con, in all caCes where

tbey are not 10 be expored 10 Cuch a force of fire as may

mell them. The bel! glafs, Ihat which ílands bOlh heat

20d ColveOls beíl, is thal in which Ihere are feweíl alka·

line Calls: Of this Con is Ihe green Germao glafs: The

beauliful white cryílal glafs is far from being equallyfer.

Ticeable.

Relons, as well as alembics, may be of difFerent

forms . For example, Come malters are apt to Cwell and

rife over Ihe neck of Ihe relOr! in Cubílaoce withoul fuf·

fering any decompofition ; when Cuch mauers are to be

diíliJled in a retan, il is proper that me body of Ihe

veC·

fel, inílead of being globular, be Jrawn out iOlo the form

gi a pear, fo as oearly tO reCemble that of a cucurbit. lo

a retort oí Ihis kind, Ibe diílance between the bouom

and the neck being much grealer thao in thoCe whofe

hodies are Cpherical, Ihe maltCrs contaioed bave much

more room for expanfion;

that the inconveoience

iJerc meOliooed is Ihereby prevented. RelOrts of this

form are caJled Englifh re10m : as Ihey hold Ihe mido

.ue place belween alembics aód common lCIons, they

l)Iay be uCed 10 diniJl Cuch matters as have a mean degree

gf volalilily belween the greareíl and the leaíl.

It is moreover proper 10 have in a laboralory Cundry

relom wilh necks of differenl diamelm. Wide necks

will be found lhe fineíl for conveying thick matters, and

fuch as rcadily become fixed

for inílaoce, fome very

tbick felid oils, bumr of aotimony,

&e.

for as Ihefe

maners acquire a confiíleoce as foon as they are out of

the reach of a cenain degree of heat, they would fooo

tbo,k up a narrow neck, aod by ílopping Ihe vapours,

which riCe al the (ame time from the relOrt, mighl occa·

fion Ihe burfling of tbe vell'e1s.

Sorne retom are alfo rnade witb an openiog 00 tbeir

llpper C!.de, like Ihat of tubulated glaCs alembics, which

is 10 be c10Ced io Ibe Came manoer wilh a glaCs ílopple.

TheCe retorlS are alfo called

I,ubulaud rtlDrll.

and oughl

alway\ to be uCed whenever it is necell'ary to iotroduce

(ren¡ matter into Ihe reton during Ibe operatioñ; feeiog

may

dODe

mew

of lhU\mvenúoD, wilbout

uo.-

IUliog aod reluling the vell'els

which ought alwayr-10

be avoided as much as poffible

One of the thing< thal moíl pcrplexes Ihe cbemills is,

the prodigious elafticilY of

Im.ny

differenl vapours,

whic~

are frequently difchargcd ",ilh impeUlofit)' dnring Ihe di·

llillalion, and are even capable of buríling the vcll'e1,

with explofion, and with dangcr lO Ihe anill. On fuch

occafions il is abfollltely oecefl:1I y to give Ihefe vapours

vent, as we (hall dire[t in ils proper place: But as Ihat

can never be done Wilhoul lofing a great maoy of them;

as Come of Ihem io panicular are

elaftic, that fcarce

aoy at allwould remain in tht vell'e1

for inllance, Ihofe

of the Cpiril of nitre, and eCpecially thofe of the Cmok¡ng

fpirit of falt : Ibe pra[tice is to make ufe of very large

receivers, of abollt eighleen or l\Venty ioches diarnerer,

tbat the'vaponrs may have fuflicienl room10 circulale io,

and, by applying ro Ihe \Vide Currace prefenled Ihem

the extenfive infide of Cnch a Iarge vefrel, may be con·

denCed ioto drops . Thefe huge retelvers are cummooly

io the form of hoJlow globes, aod are called

ha/lonl.

To give theCe vapours fhll more rOo.l1, ballons bave

beeo contrived wilh I\VO opeo gullels in each, diamelri·

cally oppofite lO one anolher : wbmof one admil! Ibe

neck of the retan, and the olher is received by one of

the gullels of a Cecond bailon of Ihe fame form, whicb i1

joioed in like manner 10 a lhird, and' fo oo.

tbis aro

tifice Ihe fpace may be enlarged at pleafure. Thefe bal·

lons with two necks are called

adGPlm.

Operalioos on bodies Ihal are abColutely li1<ed. as me·

tals, nones, fand,

&c.

require only fuch vell'els as are

capable of conlaining thoCe bodies aod refiíling the force

of fire. TbeCe vell'els are lirtle bollow POI!, of diffe·

rent dirnenfioos, which are called crucibles. Crucible,

can hardly be made of any thing bUl canb; Ihey o¡'ght

to Ime a cover of Ihe Came malerial

fimo

10 fhut Ihem

cloCe. The beíl earth we know is Ihal \lIbereor thofe

pOIS are made

which bUller is brought from Bretagne:

TheCe pots themfelve, are exceeding good crucibles

aod

tbey are almoíl Ihe only ones Ihal are carable of holding

glaCs of lead in fufioo, wilhoul being p'enetrated by ir.

For Ibe roafling of ores, Ibal is, freeing Ihem by

tbe help of fire from their Culphureous and arCenical

pans, . Iillle

~ups

made of Ihe Came malerial wilh cruci·

bIes are ufed

but Ihey are made !lal, fhallow, and wi·

der aboye rhan be.low, Ihal Ibefe volatile mallers may the

more freely exhale. Thefe .ell'els are called

lifiJ,

fcoriftm ..

They are fcarce uCed bul iD Ihe

docimalli~

an, thal is, io rnakiog Cmall all'ay! of

ores.

7he Theory

crmjlru8ing

the

FurnaceJ

moft

commonly ufro in Chemijlry.

SKILL in conduéting aod applyiog tire properly, and

delermining its difFereol degrm, is of very

g~eat

cooCe·

quence 10 the fuccefs of chemical operations.

As il is-exceeding dillicull 10 govern and moderale tbe

a[tion of fire, wheo Ihe vdJ'ds in wbich any operatioo i,

performed are imrnedimly expoCed to il, cbemiíls have

contrived to convey beal to their velTels, in nice opera.

tions, tbrough dtffereol Olediums, wbich they place

oc~

cafionly

betwccn

tbofe

ve1fels

aIld

Ibe ÚIe.

TJ¡of'c