GLASS, 



and houfes to har* confifted of a thick, fometimes white, but 

 softly blue-green, metal. 



According to venerable Bede, artificers (Icilled in making 

 glafs were brought over into England, in the year 674, 

 by abbot Benedict, who were employed in glazing the 

 church and monaftery of Weremouth. According to 

 others, they were firft brought over by Wilfrid, or Wig- 

 frid, bifhop of Worcefter, about the fame time, or, as 

 others think, at a later period, A. D 726. Till this time 

 the art of making glafs, or at lealt of applying it to this 

 purpofe, was unknown in Britain : though glafs windows 

 did not begin to be ufed before the year 11 So: till this 

 period they were very fcarce in private houfes, and con- 

 sidered as a kind of luxury, and as marks of great magni- 

 ficence. Italy had them firft, next France, from whence 

 they came into England. 



Leo Oftieniis (A. D. 760) fpeaks of the windows in 

 liis time being made with glafs-plates fixed in lead, and 

 faftened together with iron. Anaftafius, an hiftorian of 

 Rome, who was hbrarian to the pope, mentions, that in 

 tlie pontificate of Leo IIL who became pope about the 

 year 800, painted glafs in windows was in ufe. The fta- 

 tutes of the church of Traguier, in Lower Britany, about 

 the year 1156, fpeak of the windows of churches and cha- 

 pels being ornamented with arms and military enfigns, 

 painted upon the glafs in them. A charter of Richard H. 

 of England, quoted by Rymer, (A. D. 1386), contains a 

 paragraph in which is mentioned glafs, together with the 

 manufacture of it for windows. 



Venice, for many years, excelled all Europe in the fine- 

 jiefs of its glafles ; and in the thirteenth century, the Vene- 

 tians were the only people who had the fecrct of making 

 cryllal looking-glaffes, and which they performed by blow- 

 ing, much in the fame manner as a confiderable quantity of 

 the common mirror-glafs is now manufaftured. The great 

 glafs-works were at Muran, or Murano, a villagenear the city, 

 which furniflied all Europe with the fineft and largeft glaffes. 



The glafs manufacture was firft begun in England in 1557 : 

 the finer fort was made in the place called Crutched Friars, 

 in London ; the fine flint glafs, little inferior to that of 

 Venice, was firft made in the Savoy-houle, in the Strand, 

 London. This manufafture appears to have been much 

 improved in 1635, when it was carried on with fea-coal or 

 ^it-coal, inftead of wood, and a monopoly was granted to 

 iir Robert Manfell, who was allowed to import the fine 

 Venetian fliut glaffcs for drinking, the art of making which 

 was not brought to perfedtion before the reign of WiUiam 

 IIL But the firft glafs plates, for looking-glafies and 

 coach windows, were made in 1673, at Lambeth, by the 

 encouragement of the duke of Buckingham ; who, in 

 1670, introduced the manufafture of fine glafs into England, 

 by means of Venetian artifts, with amazing fuccefs. So 

 that within a century paft, the French and Englilh have not 

 only come up to, but even fiu-pafled, the Venetians, and we 

 are now no longer fupplied from abroad. 



The French made a confiderable improvement hi the art 

 of glafs, by the invention of a method to caft very large 

 plates, till then unknown, and fcarce praftifed yet by any 

 but themfelves and tlie EngUfli. That court applied itfelf 

 with a laudable induftry to cultivate and improve tlie glafs 

 manufacture. A company of glafs-men was eltabliflied by 

 letters patent ; and it was providea by an arret, not only 

 that the working in glafs fhould not derogate any thing 

 from nobihty, but even that none but nobles ftiould be al- 

 lowed to work therein. 



It was in the year 1665, under the miniftry of the great 

 Colbert, that a company for " blowu-miiTor-glafs" was 



firft eitabhdied r.ear Cherbourg, in Normandy, on the plafi 

 of the Venetian manufadure ; but the beautiful art of 

 carting glafs was invented in France about the vear i68«<; 

 by a perfon of the name of Abraham Tlicvart ; and a com- 

 pany was foon eilabliflied for this branch of manufacture, 

 wliich was firft carried on at Paris, and foon after removed 

 to St. Gobin, where it ftill cxifts in full zctivily, and undi- 

 miniftied reputation. An cxtenlive manufactory of ihin 

 kind was firft eftabliftied among us near Prefcot ia Lan- 

 cafliire, about the year 1773, by a refpeftable body of 

 proprietors, who were incorporated by an act of par- 

 liament. They ftruggkd lor a confi.lerable time with 

 difficulties ; but bcnig ncbly relieved and encouraged 

 by government, they have fucceeded in producing 

 plates rivalling, if not furpalfing in fizc, quality, or bril- 

 liancy, the m.oft celebrated continental manufactures. Thi» 

 company furnifiies, at Albion Place, London, plates of va- 

 rious dimenfions, from 12 to 144 inches in lengtli, and from 

 10 to 72 inches in breadth ; and alfo convex and concave 

 mirrors, from 12 to 36 inches in diameter. 



Gl.^.s.s, Ingrcdknis of. The materials ufed in the compontior. 

 are fome faline fubftance and fomc fort of filiceous earth. 



1. The firft ingredient v.-c ftiall fptcify is fi!cx or ftonc. 

 The beft is that which will melt, and which is white and 

 tranfparent. It is this that gives confiftencc andfirmnefs to 

 the glafs. This is found inincipally in Italy, being a 

 fort of ftony fubftance called tarfo : the next is puocol't, or 

 cuogola, a fort of pebbles found at the bottoms of rivers, 

 and gathered for the Venetian mamifadture out of the river Po, 

 which are faid not to be inferior in whitcnefs to alabafter. 



Indeed, nothing makes finer and clearer glafs than common 

 flint, diftinguiflied for this ufe by its clear tranfparent, 

 black colour ; this, before it is ufed, muft be licated red- 

 hot, and then immediately quenched in cold water. Tlio 

 heat whitens it, and the water caufes it to fplit in ever)- di- 

 rection, and facihtates the grinding of it. The charge of 

 preparing this deters tlie glafs-men from ufing it. The 

 rounded fragments of quartz, found in the beds of rivert 

 among mountains, are fometimes ufed in foreign countries, 

 being firft heated and ground to powder. Indeed, the 

 preparation neceffary for ftone, in general, is to calcine^ 

 powder, and fearce it. 



Ant. Neri obferves, that all white tranfparent ftoncs, 

 which will not burn to lime, are fit to make glafs ; and that 

 all ftones which will ftrike fire with fteel, are capable of 

 being employed in making of glafs. But lliis latter rule. 

 Dr. Meriet obferves, docs not hold nniverfally. Where 

 proper ftone cannot be had, fand is ufed ; and it is now 

 almoft the only kind of fubftance employed in the Britifh 

 manufaftures of glafs. The beft for this purpofe is that 

 which is white, fmall, and fhiuing: examined by the micrc- 

 fcope, it appears to be fmall fragments of rock cryftal. For 

 green glafs, that which is of a foft texture, and more 

 gritty ; it is to be well ^^aftled, which is all the preparation 

 it needs. Our glafs-houfes are furniihcd witli white fand 

 for their cryftal glaffes from Lynn in Norfolk, and Maidftone 

 in Kent, and from, the weftern extremity of the Ific of 

 Wight ; and with the coarfer, for green gl.ifs, from Woolwicl.. 



2. The fecond ingredient in the manufacture of glafs is 

 an alkali, which is cither foda, or ]>ot-alh. It is alwayi 

 ufed at firft in the ftate of carbonat, though the carbonic 

 acid flies off in the procefs. For the nieihod of preparing 

 each, fee Carbonat. Thcfc alkalies are ufed in different 

 degrees of purity according to the required quahty of the 

 glafs. The fineit fort of glafs requires the beil pcarl- 

 afties, purified by folution and evaporation, to dr\-- 

 nefs ; bat fior inferior glaffes coarfer alkidies, fuch as barilla, 



S f : wei>iU 



