304 SALTS 



The constituents per cent, according to this 

 view of the subject, would be 



Carbonic acid 36-263 



Magnesia 43*956 



Water 19*781 



100-000 



numbers which approach sufficiently near the 

 result of the analysis to give much probability 

 to the opinion. 



g. Borate of magnesia. The mineral called 

 boracite, which crystallizes in cubes, having 

 their alternate angles truncated, and which has 

 a specific gravity of 2*566, is a compound of bo- 

 racic acid and magnesia, and from the best ana- 

 lyses of it hitherto made, it seems to be a bibo- 

 rate of magnesia, composed of 



2 atoms boracic acid 6 

 1 atom magnesia 2-5 



8-5 



It is destitute of water. 



Phosphate, 7. Phosphate of magnesia. When this salt is 

 obtained by mixing together solutions of sul- 

 phate of magnesia and phosphate of soda, it 

 crystallizes in small flat four-sided prisms, hav- 

 ing a silky lustre, and destitute of taste. It is 

 composed of 



1 atom phosphoric acid 3-5 

 1 atom magnesia 2-5 



7 atoms water 7*875 



13-875 



