GLASS. 



again melted, and tinged of the colour required. Some of 

 tliefe pieces ai'e brought to the Ihape required by blowing 

 with the breath ; fome arc ground on a lathe, and others 

 arc emboffed in the fame manner as filver. Sidon was for- 

 merly famous for thefe manufailures, as fpecula or looking- 

 gliifles were firft invented there ; " fiquidem ctiam fpecula 

 excogitaverat." Such is the ancient method of making 

 glafs, defcribcd by Pliny. In his time, it was made with fund 

 found at the mouth of the river Vulturnus, upon the fliore, 

 for iix miles betv.-een Cumse and the Lucrine bay. This 

 Tand was very fine, and was ground to powder vv-ith a ball or 

 fplierc and a mill. It was then mixed v.-ith three parts of the 

 foflil alkali, either by weight or meafure ; and being fufed, 

 was conveyed in a liquid ftate into other furnaces, where 

 it was formed into a mafs, called " ammonitrum," (or fand 

 combined with the foffil alkali,) which mafs was melted, 

 jind became then pure glafs, and a mafs of white vitrified 

 matter. The fame method of making it prevailed in Spain 

 and Gaul. Glafs was llkewife made to imitate the lapis 

 Obfidianus, a fubflance found by a perfon of the name of 

 Obfidius, in Egypt and Ethiopia. This fubilance was of a 

 very black colour, yet obfcnrely tranfparent, and often 

 placed among fpecula in the walls of rooms, to reflett the 

 fhadow of objefts. It was alfo ufed for the fame purpofe 

 as gems (probably for engraving upon) and even for ftatues. 

 Pliny mentions, that he faw lolid ftatues of the emperor 

 Aucruflns made of this material ; and the fame emperor 

 dedicated four elephants made of the fame fubilance in the 

 temple of Concord. It feems to have been ufed from great 

 antiquity ; but in the time of Pliny the artificial imitation of 

 it by glafs was ufed inftead of the native material ; and he 

 intimates that the black colour was produced by fome 

 colouring ingredient. The Romans had likewife an opaque 

 red kind of glafs, ufed for plates and diihes for the table, 

 called " hxmatinon,'' one of various colours, called 

 " myrrhinuni,'' a white, a clear red, a blue, and indeed moft 

 other colours. Pliny obfervcs, that no fubilance was more 

 manageable in receiving colours, or being formed into fhapc, 

 than glafs. The perfcftly clear glals, which bore the 

 greate'it rcfemblance to cryflal, was, however, moft valued. 

 Nero gave for two cups, with two handles to each, and of 

 no extraordinary fize, 6000 fefterlia, or nearly 50,000/. fter- 

 ling. The inferior kinds were not uncommon, as PHny 

 informs us, that the ufe of glafs cups had nearly fuperfcdcd 

 . tliofe of gold and filver. We fliall here add, tliat Pliny knew 

 the power of a hollow glafs globe, filled w'ith water, 

 in concentrating the rays of light, fo as to produce 

 flams in any combuftible fubftance upon which the focus 

 fell; and he alfo mentions, that fome furgeons in his time 

 made u/e of it as a cauftic for ulcers (1. xxxvii. c. 2.). 

 He was likeu-ife acquainted with the comparative hardnefs 

 of gems and glafs, as he obferves, that the lapis Obfidianus 

 would not fcratcli the true gems ; and he alfo mentions 

 (1. xxxvii. c. 13.), the coimterfeiting of the latter, in his 

 time, as a vei-y lucrative art, and brought to great perfec- 

 tion. He alfo fays, that glafs might be cut or engraven 

 upon by m.eans of diamonds, which art is evidenced by the 

 antique gems fo frequently found. (See Gem.) Jofephus, 

 (I. ii. c. 10.) mentions the fand of the river Belus, in 

 Galilee, as fit for making glafs. 



The firft time we hear of glafs made among the Romans 

 was in the reign of Tiberius, when Pliny relates that an 

 artift had liis houfe demoliflied for making glafs malleable, 

 or rather flexible ; though Petronius Arbiter, and fome 

 others, affure us, that the emperor ordered the artift to 

 be beheaded for his invention. In the tim.e of Martial, 

 (A.D. S4) glafs was not only brought to great perfettion, 



7 



and in common ufe for drinking veffels, but was employed 

 (as it feems) for bottles in which wine was kept, and like- 

 wife for pots to hold flowers. (Epig. 1. 1. ii. 22. 40. 1. iv. 86.) 

 Galen (A.D. 143) frequently mentions glafs in feveral 

 parts of his works, and feems to have been well acquainted 

 with the method of making it. Apuleius (A.D. 161) 

 mentions the manufafture of glafs cups, in his time, as 

 highly wrought and carved in various vi'ays, and of great 

 value. Alexander Aphrodifienfis (A.D. 214) a Greek 

 writer, and a commentator on Ariftotle, has feveral re- 

 marks on glafs refpefting both its brittlenefs, efpecially on 

 change of temperature, and its tranfpareney. 



The manufatlurers of glafs formed a company at Rome, 

 and had a ftreet affigned them, in the firll region of the city, 

 near the Porta Capena. A tax was laid upon them by 

 Alexander Severus (A.D. 220) which fubfifted in the 

 time of Aurelian, and probably long after. 



Mr. Nixon, in his obfervations on a plate of glafs found 

 at Herculaneum, which was deftroyed A. D. Po, on which 

 occafion Phny loft his life, offers feveral probable conjec- 

 tures as to the ufcs to which fuch plates niiglit be applied. 



Such plates, he fuppofes, might fcrve for fpecula, or 

 looking-glafles ; for Pliny, in fpeaking of Sidon, adds, 

 " fiquidem etiam fpecula excogitaverat ;'' the reflection of 

 images from thefe ancient fpecula being efFefted by bc- 

 fmearing them behind, or tinging them through with fome 

 dark colour. (See MinRor..) Another ufe in which thty 

 might be employed, was for adorning the walls of tlieir 

 apartments by way of wainfcot, to which Pliny is fuppofed 

 to refer by his intre,e camene (lib. xxxvii. cap. 25. § 64- )• 

 Mr. Nixon farther conjectures, that thefe glafs plates might 

 be ufed for windows, as well as the laminas of lapis Ipc- 

 cularis and phengites, which were improvements in luxury 

 mentioned by Seneca, and introduced in his time, Ep. xc. 

 However, there is no pofitive authority relating to tlie 

 ufage of glafs windows earlier than the clofe of the third 

 centm-y : " Manifeftius eft,'' fays .Latlantius, " mentem efle, 

 per ocvdos ea qure funt oppofita, tranfpiciat, quafi per 

 feneftras lucente vitro aut fpeculari lapide obduftas.'' De 

 Opificio Dei, cap. 5. See Phil. Tranf. vol. 1. art. 80, 

 p. 601. vol. lii. art. 23. p. 123. 



St. Jerome (A. D. 422) fpeaks of windows formed of 

 glafs, melted and caft into thin plates, as being ufed in his 

 time. Paulus Silentiarins, a poet and hiftorian of the fith 

 century (about A.D. 534), fpeaks of the brightnefsof the 

 fun's rays, pafiing through the eaftern windows of the 

 church of St. Sophia, at Conftantinople, which windows 

 were covered with glafs. Gregory of Tours (A. D. 571) 

 laments tlie devaftations frequently committed on the v.'in- 

 dows of the churches by the ravages of war. Johannes 

 Philoponus, who lived about the year 630, or, as fome lay, 

 a centiu-y earlier, not only fpeaks of glafs, but of the panes 

 being faflened in with plainer, much in the fame way as at 

 prefent. 



If the opinion of Pennant, fuggefted under the article 

 AxGUixuM ovum, be well founded, we have reafon to be- 

 lieve, that, long before ' the conqueft of Britain by the 

 Romans, the art of manufafturing glafs into fuch orna- 

 ments as beads and amulets was known among the Druids j 

 and if the art was thus applied, it is not improbable to fup- 

 pofe, that it was employed for more important and ufeful 

 piu-pofes, as in the manufafture of glafs veflels. Nor is it 

 likely that the Britons derived this art from the Romans, 

 wlio preferred fdvcr and gold to glafs for the compofition 

 of tlieir drinking veflels. Befides, the glafs that was com- 

 monly ufed by the Romans was of an inferior quality, and 

 appears from foniq remains of it difcovercd at their llations 



and 



