zinc 



ACIDIFIABLE COMBUSTIBLES. 



the water, which could be probably accounted 

 for, if we knew the previous treatment which the 

 mineral had received. 



Q. SILICATE OF ZINC. 



silicate of This mineral was first accurately described 

 and examined by Mr. Smithson. It is easily dis- 

 tinguished from the other calamines, by the pro- 

 perty which it has of becoming electric when 

 heated, which is peculiar to it. It is also very 

 generally, if not always, in crystals. 



According to Smithson's experiments, publish- 

 ed in 1803, its constituents are 



Silica . . 25 



Oxide of zinc . 68-3 



Water . . 4-4 



97-7 



Berzelius, who made an analysis of it, expressly 

 with a view to elucidate the doctrine of definite 

 proportions, found it a compound of 



Silica 



Oxide of zinc 



Water 



Carbonic acid 



Oxides of lead and tin 



99-916 



* Nouvenu Systeme Mineral, p. 258. 

 > 



