GLASS. 



upriiflit pirctS of timber, witli z crofs beam of the fame, 

 for fiipportin<j the glafs and tube, which are kept in an 

 tjbliquc polition by the atTillant, that the mailer workman may 

 ivith a puncheon fet in a wooden handle, and with a mal- 

 let make a hole in the mafs : tliis hole is drilled at the 

 centre of the ball that terminates the cylinder, and is 

 about an inch in diameter. When the glafs is pierced, 

 the dcfcdts of it are perceived ; if it is tolerably pcrfett, 

 the workman lays the tube horizontally on a little iron 

 trefiel, placed on the fupport of the aperture of the furnace. 

 Having expofed it to the heat for about half a quarter ot an 

 hour, he takes it away, and with a pair of lung and broad 

 Ihcars, extremely (harp at tlic end, widens the glafs, by inii- 

 Duating the fhtars into the hole made with tlie puncheon, 

 frhilll the afTillant, mounted on the ftooT, turns it round, till, 

 at lall-, the opening is fo large as to make a pcrR-ft cylinder 

 at bottom. When this is done, the workman lays his glafs 

 upon the treffel, at the mouth of the furnace, to heat it : he 

 then gives it to his afntlaiit on the ftool, and with large 

 ihears cuts the mafs of matter up to half its height. There 

 is at the mouth of the furnace an iron tool, called pontil, 

 which is now heating, that it may unite and coalefce with 

 the glafs jull cut, and perform the office which the tube did 

 before it was fcparated from the glafs. This pontil is a piece 

 of iron, fix feet long, and in tlie form of a cane or tube, 

 liaving at the end of it a fmall iron bar, a foot long, laid 

 equally upon the long one, and making with it a T. Tins 

 little bar is full of the matter of the glafs, about four inches 

 thick. This red-hot pontil is prefented to the diameter of 

 the glafs, which coalefces imn-.edi:itely with the matter round 

 the pontil, fo as to fuppcr^ the glafs for the following ope- 

 ration. When this is done, they feparate the tube from tl-.e 

 glafs, by ftrikingafew blows v.ith a chifFel upon the end of 

 the tube, which has been cooled ; fo that the glafs breaks 

 direftly, and makes this feparation, the tube being difchavgcd 

 of the glafs now adhering to the pontil. They next prelent 

 to the furnace tiic pontil of the glafs, laying it on the treffel 

 to heat, and redden the end of that glafs, that the workman 

 may open it with his (hears, as lie has already opened one 

 end of it, to com^;lete the cylinder ; tlie afliftant holding it 

 on his ilool as before. For the lall time, they put the pontil 

 on the treffel, that the glafs may bcccm.c red-hot, and the 

 workman cuts it quite open with his f.iears, right cver- 

 again!l the fore-mentioned cut ; this he does as before, 

 taking care that both cuts are in the fame line. In the 

 mean time, the man who looks after tiie carquaifies, comes 

 to receive the glais upon an iron fliovel, tv.-o feet and a half 

 Jong without tlie handle, and two feet wide, with a fmall 

 border of an inch and a half to the right and left, and 

 towards the handle of the faovel. Upon this the glafs is 

 laid, flattening it a little with a fma'l Hick a foot aud a half 

 long, fo that the cut of the gl.ds is turned upwards. They 

 feparate the glafs from the pontil, by i'riklng a few gentle 

 blows between the two with a chilTel. The glafs is then re- 

 moved to the mouth of the hot carquaifTe, wh-re it becomes 

 red-hot gradually ; the workm.an, with an iroa tool, fix feet 

 long, aud widened .• the end in form cf a club at cards, 

 four inches long, and two inches v. iJe on each fide, very flat, 

 and :.ot half an inch thick, gradually Lfts up the cut part of 

 the glafs, to unfold it out of its form of a flattened cy- 

 linder, and render it fmooth, by turning it down upon the 

 hearth of the carquailis. The tool, iJready defcribed, being 

 infumated within the cylinder, perf ;rms this operation, by 

 being pulhed hard againlt all the parts of the g!afs. When 

 the g afs is thus m.iue quite fmooth, it is pufhed to the 

 bottf.m of the cirquaifle, or annealing furnace, wiiha fiv.all 

 iron raker, uiij r.in^ed there with a little iron hook. When 



I 



the carquailTe h full, it is ttoppcd and cemented as in the 

 cafe of run glafics, and the glais remains there for a fort- 

 night to be annealed ; after which time, they are taken out 

 to be poliihed. A workman can make but one glafs in an 

 hour, and he works and rells for fix hours alternately. 



It may be obferved, that looking-glaffes, thus blown, 

 fliould never be above forty-five, or at moll fifty inches long, 

 and of a breadth proportionable. Tliofe exceeding thefe 

 dimenfions, as we frequently find among the Venice glaffes, 

 cannot have the thicknefs fufiicient to bear the gi'inding y 

 and, befides, are fubjtc^ to warp, which prevents them from 

 regularly reflecting objedls. Whereas plates as large as 

 nine feet in length and proportionally wide, have been ma- 

 nufaftnred by calling. 



Cnjlhig or niniiii!^ ^'"'S' I'"<:khig-nlnfs plates. This art, ns- 

 we have oblerved in the Hijlory oj CjL.M^i, is of French in- 

 vention. It is owing to the .Sieur Abraham Tlievart, who 

 firll propofed it to the court of France, in 1688 



It is performed much like the calling of flieet-lcad among- 

 the plumbers ; and by means hereof we are not only enabled 

 to make glaffes of more than double the dimcnfions of anv 

 made by the Venetian way of blowing ; but alfo to call all 

 kinds of borders, moulding.^, &;c. 



The furnaces fbr melting the materials of this manufacture 

 are of large fize, being about 1 8 feet long and 15 wide ; and 

 thofe for annealing the glaffes, \\ hen formed, are much more 

 fo. Round a melting-furnace, there are at leall twenly-fou r 

 anneahng furnaces or ovens ; each from twenty to twenty 

 live feet long ; they are called carquaiffcs : each carquailfe 

 has two tiii'arts, or apertures, to put in wood, and two- 

 chimnie?. Add, that befide the annealing furnaces, &c- 

 there are others for making of frit, and calcining old piecesr 

 of glafs. 



All thefe furnaces are covered over \\ith a large Ihed y 

 under which are likt wife forges, and work-houfes for fmiths, 

 caif'enters, &c. continually employed in repairing and keep- 

 ing up the machines, furnaces, &c. as alfo lodges, and apart- 

 m.ents for thefe, and the other workmen, employed about 

 the glafs, and keeping up a perpetual fire in the great fur- 

 nace ) fo that the glafs-hcufe, as that in the cafllc of St. Go- 

 bm, in the forcit of Fere, in the Soilfonois, appears more 

 like a litLle city, than a manr.fatlor)-. 



Theinfide of furnaces is formed of a fort of bailed eorth, 

 or refraftory clay, proper to fuftain the aCliou of fire ; and 

 the fame earth ferves alfo for m.elting-pots, cillerns, &c. 

 The furnaces feldom Idt above three years ; after whicU 

 they are to be rebuilt, Irom bottom to top ; and to keep 

 them good, even for that time, the infide mull be refitted 

 every fix m.cnths, at which time the fire is extinguiihed. 

 The fmelliflg-pots are as big as wine hogfiicads, about three 

 feet in height, and in diameter ; and contain above two 

 thoufand weight cf metal. Tliey arc in the foyn cf an in- 

 verted and truncated cone. The cillerns, or pans, culled 

 " cuvettes," are much fmallcr, being about th-i'tv-fix ihchl'S 

 long, eighteen inches wide, and as many deep ; and ferve for 

 the conveyance of liquid glafs, which is drawn out of the 

 pots to the callinc tables. Tliey do not contain much more 

 than a fixth, or when large plates a.^e call, a third of the 

 pot^. 



VvTien the furnace js in condition to receive the pots and 

 ciflerns, they heat it red-hot, which requires fifty cords, or 

 a hundred cart-loads of wood. That kind of wood which 

 emits the largeil and brightell flame, without much refinous 

 fmoke, is preferred. This done, they fill tlie pots with the 

 materials, or ioda and land, winch is done at levtral times, 

 to facilitate the fufion. When the mutter is fufheientlv 

 vitrified, refined, and fettkd, wh'ch ufually happens in 



thirty- 



