300 SALTS 



heated in a platinum crucible till every thing 

 was expelled except the base : the residual mag- 

 nesia weighed 2*5 grains. Hence, the salt is a 

 compound of 



1 atom nitric acid 6-75 



1 atom magnesia . 2-5 

 6 atoms water . 6-75 



16 



carbonate, 3. Carbonate of magnesia. This salt occurs 

 native in great abundance in Hindostan, where 

 it constitutes a range of rocks extending a con- 

 siderable way.* Its colour is snow white, and 

 its specific gravity 2*7374 ; it is rather harder 

 than fluor spar, and it dissolves very slowly in 

 acids, unless it be reduced to powder, and the 

 action of the acid promoted by heat. I found 

 the constituents of a very good specimen of this 

 mineral as follows : 



Carbonic acid . 51-627 



Magnesia . 47 566 



Deutoxide of manganese 0-807 



100 



Stromeyer analyzed a specimen of the same 

 mineral from Baumgarten in Silesia. Its con- 

 stituents were 



* For the specimen which I subjected to analysis I was indebted to the 

 friendship of Mr. Babington of London. 



