MM. Wohler and Michel on Alloys of Aluminum. 377 



ably well in dry air, but first becomes covered with a layer of 

 oxide. 



It burns with difficulty in the blowpipe flame, because it 

 becomes covered with a layer of lime ; but the combustion of its 

 wire gives rise to red scintillations of great beauty. 



In the anticipation of obtaining crystallized titanium, AVb'hler* 

 fused a mixture of titanic acid with cryolite and a piece of alu- 

 minum, together with a flux of chloride of sodium and potassium. 



The aluminum was found afterwards in the form of a lamellar 

 porous slag, which, when treated with soda lye, left a quantity 

 of lustrous brownish crystals ; by treatment with hydrochloric 

 acid these became quite colourless. The body is a combination 

 of aluminum with titanium and silicon, but not apparently in 

 any definite proportions. It is decomposed by chlorine, forming 

 chloride of titanium, silicon, and aluminum. It is slowly 

 attacked by hydrochloric acid, forming hydrogen gas and oxide 

 of silicon. 



Michelf, at Wohler' s suggestion, has prepared a series of 

 compounds of aluminum and the metals. 



Tungsten- Aluminum was obtained by melting together 15 parts 

 of tungstic acid with 30 of cryolite, 30 of chloride of potassium 

 and sodium, and 15 of aluminum. On treating the slag with 

 hydrochloric acid, the excess of aluminum was dissolved out, and 

 the compound was left as a grey crystalline powder, containing 

 individual crystals several millimetres in length, which under 

 the microscope were found to consist of rhombic prisms with 

 terminal faces. Their spec. grav. was 5*58, and they were very 

 hard and brittle. Their formula was found to be Al 4 W. Treated 

 with caustic soda, all the aluminum was dissolved out, and pure 

 tungsten left. 



Molybdenum-Aluminum. — Molyhdic acid was dissolved in 

 hydrofluoric acid, and the solution evaporated to dryness, and 

 fused with cryolite, flux, and aluminum in the manner de- 

 scribed above. The regulus, by successive treatment with soda 

 and nitric acid, yielded a crystalline powder which was found to 

 consist of iron-grey rhombic prisms. Analysis led to the formula 

 Mo Al 4 . 



Manganese- Aluminum. — Obtained by fusing 10 parts of 

 chloride of manganese, 30 of chloride of potassium and sodium, 

 and 15 of aluminum. The regulus, by treatment with dilute 

 hydrochloric acid, left a quantity of interwoven stellate-group 

 needles, some of them 5 or 6 lines long. The needles were 

 quadratic prisms of the specific gravity 3*402. The compound 

 is easily dissolved by concentrated hydrochloric acid. The analysis 



* Liebig's Annalen, February 1860. f Ibid. July 1860. 



Phil. Mag. S. 4. Vol, 20. No. 134. Nov. 1860. 2 C 



