378 MM. Heintz and Richter on Artificial Boracite. 



indicated the formula Mn Al 8 » Part of the manganese was 

 replaced by iron. 



Iron-Aluminum. — Obtained by fusing aluminum with proto- 

 chloride of iron, and the alkaline flux. The regulus was very 

 crystalline, and on careful treatment left the compound in fine 

 hexagonal prisms. The analysis pointed to the formula Fc Al 2 . 



Nickel- Aluminum. — Obtained in a similar manner to the above 

 compounds, in large crystalline scales of a tin-white colour. Its 

 specific gravity is 3*647. It is readily soluble in concentrated 

 hydrochloric acid. Its composition is NiAl 6 . 



M. Michel has obtained titanium-aluminum in microscopic 

 quadratic plates ; his analysis led to the formula Ti Al 3 . 



Heintz has communicated* some experiments of Richter on 

 the preparation of artificial boracite. 200 grms. of a mixture of 

 chloride of sodium and chloride of magnesium were mixed with 

 5 grms. of a compound of boracic acid and magnesia, obtained 

 by precipitating a boiling solution of sulphate of magnesia and 

 borax by carbonate of soda. To the mixture thus prepared 10 

 grms. of finely powdered boracic acid were added, and the whole, 

 well mixed together, heated in a platinum crucible. The fused 

 mass was heated with dilute hydrochloric acid, which left undis- 

 solved a crystalline powder. This powder was seen under the 

 microscope to consist of two kinds of crystals, some of a pris- 

 matic form, while others were tetrahedra and octahedra. On 

 digesting this mass for several days with hydrochloric acid, the 

 former were dissolved, while the latter were scarcely if at all 

 attacked. These latter were found on analysis to have the com- 

 position 6MgO, 8Bo 3 , MgCl, which is the formula of boracite. 

 When heated, they exhibited the pyro-electrical phenomena cha- 

 racteristic of the powder of tourmaline. 



The prismatic crystals appear to be a mixture of two com- 

 pounds, one of which Heintz supposes has the formula MgO Bo 3 , 

 and the other the formula 2 MgO Bo 3 . 



Nordenskjold and Chydeniusf describe some experiments on 

 the crystallization of thoria. 



Thoria, prepared by the ordinary method from orangite, was 

 mixed with four times its weight of borax glass, and placed in a 

 flat platinum dish, which, coated with magnesia, was fitted in an 

 unglazed porcelain vessel, and this again in an ordinary clay 

 crucible, and the whole exposed to the heat of a porcelain fur- 

 nace. The highest heat of the furnace continued forty-eight 

 hours, and the cooling was very slow. 



After the operation the borax glass presented two layers — the 



* Poggendorff's Annaltn, August 1860. f Ibid. 



