380 PLINY'S NATURAL HISTORY. 



CHAP. 66. - THE VARIOUS KINDS OF GLASS, AND THE MODE OF 



MAKING IT. 



In process of time, as human industry is ingenious in dis- 

 covering, it was not content with the combination of nitre, 

 but magnet-stone 94 began to be added as well ; from the im- 

 pression that it attracts liquefied 83 glass as well as iron. In a 

 similar manner, too, brilliant stones of various descriptions 

 came to be added in the melting, and, at last, shells and fossil 

 fi;tnd. Some authors tell us, that the glass of India is made of 

 broken crystal, and that, in consequence, there is none that 

 can be compared to it. 



In fusing it, light and dry wood is used fur fuel, Cyprian 

 copper and nitre being added to tho melting, nitre of Ophir 83 

 more particularly. It is melted, like copper, in contiguous 

 furnaces, and a swarthy mass of an unctuous appearance is the 

 result. Of such a penetrating nature is the molten glass, that 

 it will cut to the very bone any part of the body which it 

 may come near, and that, too, before it is even felt. This 

 mass is again subjected to fusion in the furnace, lor ;he pur- 

 pose of colouring it; after which, the glass is either blown 

 into various forms, turned in a lathe, 'or engraved 8 * like silver. 

 Sidon was formerly famous for its glass-houses, for it was this 

 place that lirst invented" mirrors. . 



81 "Magnes lapis." Sec H. xxxiv. c. 42, nnd Chapter 25 of this Book. 

 Beekmanu is of opinion that an ore of Manganese is meant, a substance 

 which has a re-semblance to tho magnet, and is of the greatest utility in 

 making glass. Hist. Inv. Vol. II. p. 237. 



*' This appears to he the meaning of "Quoniam in sc liquorctn vitri 

 quoque ut fcrruin trahere creditur." 



w In the description given by Isidornsin the " Origincs," which in other 

 respect* is similar, these words aro omitted, and it is possible that they aro 

 a gloss by some one who was? better acquainted with the Old Testament 

 than with Pliny. On tbo other hand, as Sillig rennv.ks, the Phoenicians 

 may, at an early period, have imported into Greece a substance which they 

 called '* nitre of Ophir." 



84 Sco Heckniaim, Hist. Inr. Vol. II. p. 84. 



85 '* Exeogitaverut." Beekmann would .seem to give this word tho 

 force only of " thought of," for he gives it as his opinion that attempts 

 were made at Sidon to form glass mirrors, but that the experiments had 

 not completely succeeded. '* Had this invention formed an epoch in tho 

 art of making mirrors, Pliny, in another place (1J. xxxiii. c. 4o), where 

 he describes the various improvements of it so fullv, would not havo omit- 

 ted it: but of those experiments he makes no further mention." He also 

 expresses an opinion that the Sidoniau mirrors consisted of dark-coloured 



