CHEMISTRY. 



123 



noxious vapors to such an extent that the 

 Government has limited the u burning " of 

 the ore to particular months. A new process 

 has been put in practice by MM. de la Tour 

 and Dubreil in which the ore is heated with 

 solution of chloride of calcium boiling at 120 

 0., when the sulphur melts gradually, and is 

 drawn off from the heating-tank directly into 

 molds. In the apparatus first employed, cer- 

 tain of the ores were completely disintegrated. 

 Modifications have been made in it, by which 

 ores of all kinds, even the fine powder at the 

 mines, are economically treated. The new 

 method presents great advantages over the 

 older methods, in that it allows the extraction 

 of the greater part of the sulphur from ores of 

 every kind, at a minimum cost for fuel ; that 

 by it the extraction is effected regularly under 

 protection from atmospheric influences ; that 

 the work can be carried on throughout the 

 year, as no sulphurous-acid fumes are formed ; 

 and that it permits the treatment of the ores 

 according to the demands of the trade. 



H. A. Gadsden, of London, has patented a 

 procesa for the manufacture of aluminum, the 

 new feature of which consists in bringing the 

 aluminum chloride and metallic sodium to- 

 gether in the form of vapors. The aluminum 

 chloride is formed by treating corundum or 

 bauxite with fluoride of sodium or potassium, 

 and passing chlorine through the mixture of 

 the pulverized roasted mass with charcoal. 



M. Weldon proposes to obtain aluminum by 

 fusing cryolite with calcium chloride, or some 

 other non-metallic chloride or sulphide and re- 

 ducing the aluminum chloride or sulphide with 

 metallic manganese. 



By another process H. Miwerth mixes fer- 

 ro-silicon with aluminum fluoride in molecular 

 proportions and heats the mixture to fusion. 

 Double decomposition takes place, silicon fluo- 

 ride is formed which volatilizes, and an alloy 

 of iron and aluminum remains. Aluminum 

 bronze may be obtained directly by fusing the 

 iron -aluminum alloy with copper. The alu- 

 minum unites with the copper, and the iron re- 

 mains with but a very small quantity of alu- 

 minum. Pure aluminum is obtained by heat- 

 ing aluminum chloride with silicon. 



C. 0. Hutchinson disposes of sewage-sludge, 

 or the slimy mud deposited from sewage, by 

 filtration in filter-presses of special construc- 

 tion. The press-cakes thus obtained still con- 

 tain about 50 per cent, of water, are inodor- 

 ous, and dry rapidly down to about 20 per cent, 

 of water. A mixture of equal parts of alu- 

 minum and calcium sulphates is used as a pre- 

 cipitant before filtering the sludge. The press- 

 cake is fully equal to farm-yard manure as a 

 fertilizer. At Coventry, with about 45,000 in- 

 habitants, 456 tons of wet sludge are treated 

 daily, at a cost of sixpence per ton, or of half 

 a crown per ton for the pressed cake. 



H. R. Proctor modifies Loewenthal's method 

 for the estimation of tannin, by adding a small 

 amount of pure kaolin to the solution contain- 



ing the tannate of gelatine in suspension, with 

 vigorous agitation. Thus treated, the precipi- 

 tate filters readily, without tedious waiting. 

 The author prefers to express the percentage 

 of tannic acid in terms of oxalic acid, the mo- 

 lecular weight of which (63) is not far from 

 that of quercitannic acid (62 -3 6). 



An improved process has been devised by 

 C. L. Bloxam, for the estimation of manganese 

 in cast-iron and spiegeleisen by precipitating 

 the iron as ferric phosphate in presence of 

 acetic acid, which retains the manganese dis- 

 solved. The metal is treated with hydrochloric 

 acid, ammonia, acetic acid, and sodium phos- 

 phate, for the precipitation of the iron, and the 

 manganese is afterward precipitated as the 

 crystalline, very insoluble arnmonio-phosphate. 



A new method for the volumetric estimate 

 of the nitrites, based upon the formation of 

 diazo-benzine from aniline by the action of 

 nitrous acid, has been devised by A. G. Green 

 and S. Rideal. The least excess of nitrous 

 acid remaining after the reaction is complete, 

 is indicated on adding starch and potassic 

 iodide. The estimate is accurate to less than 

 O'l per cent. The authors represent that, in 

 addition to its greater delicacy, their method 

 can be used in many cases where, owing to the 

 presence of oxidizable substances, the perman- 

 ganate process is inapplicable. 



A. Petit describes a new process for the de- 

 termination of cinchonas, by adding ammonia 

 to the ethereal solution of the powdered bark, 

 with alcohol, treating with sulphuric acid, and 

 precipitating the alkaloids with caustic soda. 

 The acid solution of the alkaloids is again 

 treated with ether and ammonia for the re- 

 moval of those that are soluble in ether, after 

 which sulphuric acid is again added, and the 

 quinine sulphate is made, by saturating with 

 ammonia and boiling, to separate in the form 

 of fine crystalline needles. 



Industrial Chemistry. In a report on glucose, 

 made by a committee of the National Academy 

 of Sciences, for the Commissioner of Internal 

 Revenue, besides the mode of manufacture of 

 starch-sugar, and the nature of the products 

 obtained, attention is given to the effect ot 

 those products on health. So far as the prod- 

 ucts made from corn-starch are concerned, 

 no experiments had been made with reference 

 to their effects upon the system. The pure 

 chemical substances, dextrose, maltose, and 

 dextrine, derived from the manufacture, are cer- 

 tainly not injurious, but there may be impuri- 

 ties in the commercial product, or, when fer- 

 mentation of the commercial products takes 

 place, substances may be developed, or suo- 

 stances may be left uufermented, that are of an 

 injurious character. Experiments have been 

 made in Germany with dextrose from potato- 

 starch that gave opposite results. Schmitz and 

 Nessler found the fermented products of pota- 

 to-sugar to cause sickness in cats and dogs, and 

 in some cases in men. Freiherr von Mering, 

 on the other hand, experimented in much th 



