184 ACIDIFIABLE COMBUSTIBLES. 



atom of water. This, united to a quantity of 

 anhydrous carbonate, weighing 1*31 grain, a- 

 mounts to 0-276 grain. There still remains 

 0-183 grain of water to be disposed of. It is 

 probably united* with oxide of zinc in the mine- 

 ral, so as to form the common hydrate of zinc, 

 composed of 1| atom water, united to 1 atom 

 of oxide of zinc. Now, 1-6875 (H atom of 

 water) : 5-25 (an atom of oxide of zinc) : : 0-183 

 (water still unaccounted for) : 0-569 = oxide 

 of zinc united to this water, in the state of hy- 

 drate. 



3. Thus it appears, that 1 -429 grain of oxide 

 of zinc may have been in the state of carbonate, 

 or hydrate of zinc, reducing the amount of the 

 surplus to 0*064 grain a quantity greatly with- 

 in the limits of the unavoidable errors of ana- 

 lysis. 



We are entitled, therefore, to consider silicate 

 of zinc as a compound of 



Gives Silica . 24-893 or 1-998 



Oxide of zinc . 65-408 - 5-25 



Here the atomic weight of silica is about TTnjrrth 

 part less than 2. 



7. BISILICATE OF MANGANESE. 



Bisiiicateof Thj s mineral is found at Londbanshytta, in 



manganese 



Wermeland, Sweden ; and it is said to occur 



