G38 SCIENTIFIC RECORD FOR 1882. 



Researches on the Compounds of Gold. — P. Schottliinder has published 

 an extended research on gold and its salts, in which he describes sev- 

 eral new bodies and examines with care reactions already known. Au- 

 ro-potassium bromide forms a very Btable salt, neither deliquescent nor 

 efflorescent and obtained in large crystals. The action of manganous 

 acetate on neutral gold chloride yields a mixture of metallic gold and 

 hydrated oxide of manganese of varied composition. Hydrated gold 

 monoxide Au u 3 2 (OH) 2 forms a light crystalline powder of a pure black 

 color. Hydrochloric acid decomposes it with formation of the metal, 

 trioxide and water, titrate of goldtrioxinitrate, auryluitrate, acid 

 anrylsulphate and its potassium compouud and gold monoxysulphate 

 Au n S0 4 are further described in this paper. Schottlander regards gold 

 as divalent. (Liebig's Annalen, ccxviii, 312.) 



Manufacture of Aluminium. — Secular papers and scientific journals 

 contain notices of improved methods in the industrial preparation of 

 aluminium, some of which were patented in the year 1882, and great 

 claims are advanced as respects the economy of the processes. Alumin- 

 ium, it will be remembered, was first obtained in its metallic state by 

 Friedrich Wdhler in 1826, who decomposed the chloride by sodium, and 

 although (with one exception) aluminium is the most abundant metal 

 known, thirty years elapsed before its industrial preparation was suc- 

 cessfully accomplished. This was done by Henri Sainte Claire Deville, 

 who improved greatly the preparation of sodium, the most expensive 

 ingredient used. Still the metal has sold at the relatively high price 

 of $20 per pound, and its physical properties are such that its produc- 

 tion at cheaper rates is most desirable. James Webster, an English 

 chemist and metallurgist, has devised the following method for the 

 preparation of alumina for the purpose of manufacturing the metal: 

 Three parts of alum are mixed with one part of coal pitch, and the 

 mixture heated to 200° to 200° for about three hours. The mass is 

 cooled, broken into pieces, and hydrochloric acid of 20 to 25 per cent, is 

 poured over them, giving rise to the evolution of sulphuretted hydrogen. 

 When this gas ceases to come off about 5 per cent, of charcoal powder 

 or lamp-black is added and enough water to make a thick mass. This 

 mass is thoroughly broken up and mixed in a mill, and then worked 

 into balls weighing about one-half kilogram each. These balls are per- 

 forated to facilitate drying, and dried first in a chamber heated to 40° 

 and then in a furnace at 95° to 150°. The balls are then placed in re- 

 torts and heated to low redness for about three hours, while a mixture 

 of two parts of water vapor and one of air is passed through, so that sul- 

 phur and charcoal are converted into sulphur dioxide and carbon diox- 

 ide and thus escape. The dry residue, consisting of aluminium, oxide 

 and potassium sulphate, is removed from the retorts, cooled, ground to 

 powder in a mill, and treated with about seven times its weight of water, 

 and after boiling by means of steam, the solution containing potassium 

 sulphate is run off and evaporated to dryness. The residue, consisting 



