HYDRAULIC LIMB. 881 



roasted and calcined with a little nitric acid, yielded 0.45 

 grammes of peroxide of iron on three grammes, or 1.5 

 per 100. 



D. After the separation of the ferruginous precipitate 

 from the liquor (CJ it was treated with oxalate of potash, 

 which occasioned a voluminous white precipitate. This pre- 

 cipitate, after exposure to a high temperature, afforded 0.75 

 grammes of lime on three grammes, or 25.0 per 100. 



E. The magnesia precipitated from the liquor (DJ by 

 an excess of caustic potash, after edulcoration and strong 

 calcination, weighed 0.535 grammes on three grammes, or 

 17.833 per 100. 



F. Three grammes of the pulverised mineral were sub- 

 mitted to a strong calcination. The diminution of weight 

 occasioned by this treatment was 1.235 grammes. Now in 

 deducting i.is grammes of carbonic acid (Ji) we have 0.045 

 grammes of moisture on three grammes, or 1.5 per 100. 



We then have the following results, as the products of the 

 preceding experiments, viz. : 



(Per 100 parts.) 



