Cj the Ancients refpeol'mg Glafs. ,109 



duced by fome colouring ingredient.* But many 

 ftones commonly found, as the gray rag ftone, 

 the blue whin ftone, the Derbyfhire toad ftone, 

 and the Weflmorcland flate, will all melt into a 

 vitreous mafs of a black colour. I was informed 

 by his Grace the late Duke of Northumberland, 

 whofe knowledge in chemiflry, and natural hif- 

 tory, was very extenfive, that he once procured a. 

 pot of glafs to" be made at the Glafshoufe at 

 Newcaftle upon Tyne, of the whin ftone. The 

 glafs produced from it, was of a fine black 

 colour, and good uniform texture, and eafy fu- 

 Con J but inconvenient to be ufed for bottles^ on 

 account of its having fcarcely any tranfparency. 

 He likewife added, that it exactly refembled 

 Ibme fpecimens of what was imagined to be the 

 ancient lapis obfidianus. 



The Romans had likewife an opake red kind 

 of glafs, ufed for plates and difhes for jthe 

 table, called hsematinon, one of various colours 

 called myrrhinum, a v^'hite, a clear red, a blue, 

 and indeed moft other colours. Pliny obferves 

 of it, that no fubftance was more manageable ia 

 receiving colours, or being formed into fliapc 

 than glafs. 



The perfeiflly clear glafs, which bore the 

 greateft refemblance to chryftal, was, however, 

 moft valued. Nero gave for two cups, with two 



• Plin. HiH. Nat. L. XXXVI. Cap. zb. 



handles 



