380 pliny's natural history. [riook XXXVI. 



CHAP. 66. THE VAEIOUS KINDS OF GLASS, AND THE MODE OF 



MAKING IT. 



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

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

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

 pression that it attracts liquefied®- 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 

 sand. 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 for fuel, Cyprian 

 copper and nitre being added to the melting, nitre of Ophir®^ 

 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, for the pur- 

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

 into various forms, turned in a lathe, or eugraved^^ like silver. 

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

 place that lirst invented^^ mirrors. 



81 "Magnes lapis." See B. xxxiv. c. 42, and Chapter 25 of this Book. 

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

 which has a resemblance to the magnet, and is of the greatest utility in 

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



**- This appears to be the meaning of " Quoniam in se liquorem vitri 

 quoque utferrum trahere creditur," 



83 In the description given by Isidorusin the " Origines," which in other 

 respects is similar, these words are omitted, and it is possible that they are 

 a gloss by som.e one who was better acquainted with the Old Testament 

 than with Pliny. On the other hand, as Sillig remarks, the Phoenicians 

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

 called " nitre of Ophir." 



81 See Beckmann, Hist. Inv. Vol. II. p. 84. 



85 " Excogitaverat." Beckmann would seem to give this word the 

 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 the 

 art of making mirrors, Pliny, in another place (B. xxxiii. c. 45), where 

 he describes the various improvements of it so fully, would not have 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 



