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Ihil w~s Ihe m~ooer by whieh Ihey wroughllheir ligbls,
aud h<iglnoiogs, 00 aJl kiods of eolour.
The lirll Ihiog lo be dooe, io order 10 paiol or fiaio
glaCs, 10 Ihe modero way, is 10 defigo, aod eveo eo–
lour Ihe IYhole ¡'ubjdl úo p'per. l'heo (hey chuCe
Cueh pieees of glaCs al are clear, even, aod Cmoolh,
aod prupeT 10 re.:eive Ihe Ce".ral pans, aod proeeed to
dinribu(e (he defigo itfelf, or papers il is drawo 00,
io(o picees fuiuble to thoCe of Ihe glaC,; , Iways lakiog
eAre Ibat the glalf<s may joio io (he eOOlours of Ihe fi –
gur••• aod Ihe folds of Ihe draperies; Ihal Ihe earoa–
tlOOS, aod other fioer pam, may 001 be impaired by
the lead wilh which Ihe pieees are 10 be joined loge–
~her. The difiributioo beiog m.. " Ihey mark all Ihe
ghlfes as weJl as pape", Ibat they may be koown
agaio: whieh dooe, applying every pan of Ihe defign
upoo Ihe ¡; io(eoded for it. Ihey copy, or traosfer,
the defigo upon Ihis glaCs lYilh Ihe black eolour diluled
in gum waler, by Iraeing aod folJowing all Ihe lines
aod firokes as they appear through Ihe glafs lYilh Ihe
poiot of a peocil.
When Ihefe firokes are weJl dried, which will hap–
peo io aboul t\Vo days, Ihe work being only io blaek
aod IYhile, Ihey give a Ilighl w.afu over wilh urioe. gum
arabic, and a Itnle blaek; aod repeal il feveral limes,
aecording as Ihe Iludes are defired 10 he heighleoed,
wilh Ihis preeaulioo, oever 10 apply a oew wafh liJl
Ibe fo rmer is fuffieieotly dried.
This done, Ihe lighls and rifiogs are giveo hy ruh–
hiog ol!' the colour io Ihe reCpellive places with a
woodeo poiot, or the·haodle of Ihe peoeiJ.
As to rhe olher colours ahove-meOliooed, they are
ufed wilb gum waler, mueh as in paiotiog io mioialure;
taking eare 10 apply IhemJightly, for fear of efaeiog,
Ihe out-liDes of Ihe defigo; or eveo, for Ihe grealer fe–
(UrilY, loapply Ihem 00 Iheolherfide; eCpeeiaJly yellow,
which is very peroieious 10.lhe olher eolou(5, hy bleod–
iog Iherewilh. Aod here too, as io pieces of blaek
and IYhile, particular regard mufi allYays he had not
to lay eolour 00 eolour, or lay 00 a nelY lay, tiJl fuch
lime as Il,e former are weU dried.
It Olay he added, Ihat Ihe yeUow is the ooly eolour
Ihat peoetrates Ihrough Ihe glaCs, aod iocorporales
Iherewilh hy the 6re; Ihe refi, aod partieularly Ihe
hlue, which i. very dillieult tO uCe, remaioing 00 Ihe
furfaee, or at leafi ealering very lillle. Wheo Ihe
paioliog o( aUlhe pieees is fioifued, Ihey are earried
Ul Ihe furoace, or oveo, t9 aooeal, or bake, Ibe eo–
lours.
The furnaee here ured is fmall, huilt of hrick,
from eighleen 10 Ihirly ioehes Cquare. Al fix iochts
from Ihe hOllom is ao aperture 10 pUl io Ihe fueJ,
~nd maiotain the 6re. O.ver Ihis aperlure i8 a
grole, made of Ihree rquare hars of iroo, which tra–
verCe (he furoace, and divide il iOlo IWO p. ns . Two
ioehes above lhis partilion, is aoolher linle aperture,
Ihrough whieh Ihty lake out piem 10 examine how Ihe
cOClion goes for",ud. 00 Ihegrate is placed a Cquare
~artheo pan, fi x or Cevea ioehes detp ; aod five or fi"
-ÍDehes leCs everr ",ay Ihan Ihe pe, immr uf Ihe fur-
VOL . 11. No . 56.
. G L A
nace. 00 Ihe one fide hereof is a litlle apertUrt,
Ihrou~h \\'hieh 10 make Irials, plac~d direa ly
Ihal uf Ihe furoaces deflined for Ihe Carne er.d. In
Ih,s ran are Ihe pieees of glaCs 10 be placeo!, in Ih.
foUowing maoner. f " n, Ihe hOtlom of Ihe pJn is
eovered with Ihree Ilrata, or layen, of quiek lime
pulveriCtd; Ihofe nrata being rcparaled by IWO olhers
of old hrokco glaCs, Ihe defigo whereof is 10 Ceeur<
Ihe paioled glaCs from Ihe 100 iotenre ¡'w of the nre.
Tllis dooe, Ibe glalfes are laid horizoolaUy 00 UlC
or uppermo(! layer of lime.
Tbe r,rn ro", of glaC. ,hey cover over wilh a layer
of Ihe Carne powder, an ioeh deep; oad over Ihis Ihey
lay anolher range of glarTes, aod thus alteroalely tiJl
Ihe pao is quile fuU; laking eare IIt.t Ihe whole heap
aJways eod wilh a layer of Ihe lime.powder.
The pao heing thus preparen, Ihey cover "p the
furn ace w¡lh tiles, 00 a Cqu..e lable of cartheo ware,
c10Cely luted all rouod ; only leaving 6ve linle aper–
tures, ooe at eaeh corner, aod aoolher in Ihe middle,
10ferve as ehimoeys. Things Ihus diCpored, t.here /C–
maios oOlhiog bUllo give Ibe fire 10 Ihe wor~. The
fire for the fi r(l t!Yo l be very moderale, and
mufi be ioereaCed iD proportioo as the coélioo advances.
for Ihe fpace of teo or Iwelve hours; io whieh time
it is uCuaUy eompleated. At lafi Ihe 6re. !Yhieh al
lirfi was eharcoal, is 10 he of dry wood, Co thal .Ihe
Eame eover, Ibe whole pao, aod eveo ill'ues OUI at lhe
ehimoeys.
Duriog Ihe la(l hours', Ihey make ell'ays, from time
to time, by taking OUI pieees laid for Ibe purpofe
through Ihe lillle aperture of Ihe furoa«, aod paa, la
fee whelher Ihe yeUow he petfetl, aod Ibe olher co–
lours in good order. Wheo Ihe anoeaJiog is thoughl
fuffieiem, Ihey proceed with greal haile 10 eXlioguifh
Ihe 6re, "hich olherwife \l/ould fooo buro !.he eolour.,
aod hreak glalfes.
GLASS o[ ¡cad. See CHEMISTRV, p. ' 36.
GLASS po,ce¡ain, ¡.he oame giveo by mao] .to a modera
iovenlion of imilaling Ibe chioa·w.,. wilh ,glaC,.
The melhod of makiog il, as giveo by Mr Reamur,
who IVas Ihe 6rfl Ihal carried Ihe .ammpl 10 any de–
gree of perCetlioo, is as foUows .
The glaCs velfels 10 he cooverted into porcelaio, are
10 he pUl inlO large velfd" fuch as Ihe ecmmoa 60e
earthendifues are baked io ; or iOlo Cuffieiently Jarge eru–
eihles: Ihe V"rTeI, are lO he fi Jled wilh a mixlure of
fine while Cand, aod of fine grPCum; or planer Ilooe,
hurol iOlo whal is caJled pla(J~r of París; .aod aU lhe
iOlerflices are 10 he up Wilh Ihe Came powder, fo
Ihat Ihe glaCs vdfel. may .no where .Ioueh eilher ooe
aoolher, or tlle fides of Ihe rell'cls I"hey afe baked io.
The veOt l ís 10 be Ihen eovercJ dOIV.n, and IUled,
"od Ihe 6ft does Lhe reH of the IVork: for this is only
10 he pur jolo a common poner's furoace, and whea il
h.. fiood tf,cre Ihe uCual time of hokiog .the olher ver–
rd., il is 10 be I.kenOut, aod Ihe "hule 'ecullenlSwill
he Couod no luoger glaCi, hUI eoovc, led iOlo a while
opake fubn ancc, which is a \'cry dl'g~nl porcelaio, ao>!
has almol! Ihe properties of Ihal of china.
t .7 T Can