185 



Top A 25. 



. Very white paste 1008 



Glass of antimony • 43 



Cassius purple • 1 



Or, 



Paste 3456 



Oxide of iron, called Saffron of Mars 36 



Ruby. 



M. Douault-Wieland succeeded in obtaining excellent imita- 

 tions of rubies, by acting on the topaz matter. It often hap- 

 pened that the mixture for topazes gave only an opaque mass, 

 translucent at the edges, and in thin plates of a red colour. 

 One part of this substance being mixed with 8 parts of paste, 

 and fused for 30 hours, gave a fine yellowish crystal like paste, 

 and fragments of this fused before the blow-pipe, gave the 

 finest possible imitation of rubies. The result was always the 

 same. 



The following are proportions also for rubies : 



Paste 2880 



Oxide of manganese , . , 72 



Emerald. 



Paste 4608 



Green oxide of pure copper 42 



Oxide of chrome 2 



Sapphire. 



Paste 4608 



Oxide of cobalt 6S 



