§30 ANALYSIS OF 



Afialysis of the Hydraulic Lime used in constructing the Erie 

 Cental in the State of Neiv York. 



This mineral is greyish both in mass and powder. It is 

 without lustre. Opaque. Amorphous. Fracture irregular. 

 Fragments indeterminate. Yields readily to the knife, and 

 is easily frangible. Fine grained ; presenting an earthy as- 

 pect, its specific gravity is 2.753. 



Analysis. 



A. Three grammes of the mineral, finely pulverised, 

 were digested in a phial containing a determined weight of 

 diluted muriatic acid. The addition of the acid to the mi- 

 neral occasioned an immediate and violent effervescence. 

 After three or four hours, when the carbonic acid was sup- 

 posed to have been entirely disengaged, it was ascertained 

 that the diminution of weight amounted to i.\S grammes. 

 Hence we have 39.333 per lOO of carbonic acid. 



B. The mixture (A) was then submitted to el^uUition. 

 When all the soluble matter appeared to have been taken up 

 by the acid, the whole was evaporated to dryness. The re- 

 sidue was treated with water acidulated with muriatic acid, 

 and again moderately evaporated. It was then treated witli 

 more water, and filtered. The residue on the filter was 

 nearly colourless ; and after calcination it weighed 0.435 

 grammes. This residue was calcined with three parts of 

 caustic potash in a silver crucible, and dissolved in an ex- 

 cess of diluted muriatic acid. By subsequent evaporation 

 of the liquor, ^c. it was found to consist of 0.353 grammes 

 of silica on three grammes, or H.766 per 100; and 0.85 

 grammes of alumina on three grammes, or a. 733 per lOO. 



C. The excess of acid of the liquor (B) was neutralised 

 with causfic potash. On adding hydrosulphate of potash, 

 there was produced a black precipitate, wiiich, after being 



