M. TECHNOLOGY. 5 13 



analogous substances are rendered extremely hard when 

 treated in the manner usually indicated for metals. The fol- 

 lowing is a brief description of the method adopted by the 

 patentee : A quantity of the fused or nearly fused glass is 

 first placed in iron or other moulds to shape the material ; 

 from these it is removed to moulds of platinum, in which it 

 is reheated to partial or total fusion, and thereupon suddenly 

 deprived of its heat by immersion in a mixture of iced water 

 and salt, or other freezing mixture that produces extreme 

 cold. The substance of the process consists, therefore, in 

 heating the glass to a high temperature, and then rapidly 

 cooling it in a very frigid fluid. American Builder^ XL, 

 188. 



HARDENING GLASS, VULCAN GLASS, AND METALLIC GLASS. 



The demand of Bastie for the secret of his process from 

 the German Glass Manufacturers' Association w^as consid- 

 ered so exorbitant that it refused to treat with him further 

 in regard to it, and purchased from Peiper, of Dresden, for 

 $60,000, the process for the manufacture of the similar so- 

 called Vulcan glass discovered by him. He was not ready, 

 however, to communicate his process for several Aveeks, and, 

 in the mean time, Lubische & Riederer, near Klitschdorff, 

 succeeded in making a so-called metallic glass, which is said 

 to be identical in character with that made by his process. 

 13 (7, May, 1875, 5V3. 



HARDENING GLASS. 



It is said that a company has been formed at Bourg, in 

 France, for manufacturino; one of the new kinds of hardened 

 glass, evidently that made by M. De la Bastie. The Ger- 

 man glass-makers, not being able to purchase the invention 

 of the French company, and having learned that hardness is 

 given to glass by dipping the same, while it is heated to a 

 half-liquid state, into a hermetically closed bath of oil or 

 fat (substances which melt far below the boiling-point of 

 water), have undertaken its manufacture. In Silesia, where 

 repeated experiments have tested the qualities of De la Bas- 

 tie's glass, another new glass has been invented by Lubische 

 & Riederer, which is called metal glass, and is so hard that 

 when a pane lies on the ground, and a leaden ball of an 



Y2 



