142 



CHEMISTRY. 



standardizing permanganates, a valve made by 

 filing or blowing a hole in a glass tube open at 

 the lower and closed at the upper end. At 

 the beginning of the process, the valve stands 

 outside of the flask. The liquid in the flask 

 is rapidly heated after the iron wire is intro- 

 duced, and, as soon as the wire is dissolved, is 

 boiled to expel all air, when the tube is pushed 

 down so that the opening is inside of the open- 

 ing of the rubber cork. This prevents the air 

 from flowing back into the flask as it cools. 



Mr. H. Y. Oastner, of New York city, claims 

 to have discovered an expeditious and cheap 

 method of preparing the alkali metals, through 

 reduction of their hydrates or carbonates by 

 the carbide of a metal or its equivalent. His 

 process requires only a comparatively moder- 

 ate temperature, and is represented as giving a 

 full yield of the metal equivalent in the case 

 of sodium, to 90 per cent. from each charge. 



G. C. Caldwell and S. W. Parr have observed 

 that the determination of fat in milk by De 

 Fecamp's lacto-butyrometer was liable to va- 

 riations which seemed to depend upon differ- 

 ences in the feed of the cow. Tollens and 

 Schmidt improved upon the method, and ob- 

 tained more satisfactory results, but still left 

 room for closer accuracy. The authors pro- 

 pose a method as a substitute for that given by 

 Tollens and Schmidt. Their lacto-butyrometer 

 differs from that originally given by Marchand 

 only in being open at the bottom as well as at 

 the top. Their process consists in treating the 

 milk in the proportion of lOcc. with 8cc. of 

 ether and 2cc. of 80 per cent, alcohol ; shak- 

 ing well and adding Ice. of ordinary ammonia 

 diluted with about its volume of water ; shak- 

 ing; adding lOcc. of 80 per cent, alcohol; and 

 shaking again. The tube is then put into water 

 at from 40 to 45 C. and kept at that tempera- 

 ture till the ether-fat solution separates ; after 

 which it is cooled in water at 20 C., and the 

 reading taken from the lowest part of the 

 surface-meniscus to the line of separation be- 

 tween the ether-fat solution and the liquid be- 

 low it. This method is found "capable of a 

 degree of accuracy that leaves nothing to be 

 desired." 



Industrial Chemistry. In one of his last ad- 

 dresses to the French Academy, M. Dumas 

 called attention to the numerous benefits per- 

 taining to the chemical industries which have 

 taken their departure from the Leblanc process 

 for the extraction of soda from sea-salt. First, 

 the working of the process placed at the dis- 

 posal of the soap-makers, the glass-manufact- 

 urers, the bleachers, and the paper-makers, all 

 the alkali they needed, and gave to all indus- 

 tries unlimited quantities of sulphuric and hy- 

 drochloric acids at extremely low prices. The 

 second result was the introduction of chloride 

 of lime for the bleaching of vegetable tissues. 

 Next arose the question whether it was wise 

 to depend upon the sulphur of Sicily, which 

 might at any time be enormously advanced in 

 price; andiron pyrites, previously worthless, 



was utilized for the manufacture of sulphuric 

 acid. The price of soda becoming reduced by 

 competition, a new source of profit was found 

 in the manufacture and sale of chloride of lime. 

 A residue of sulphate of lime was formed, whic,h 

 was likely to prove a great nuisance, when the 

 danger was removed by the invention of a pro- 

 cess for regenerating the soda which was left 

 from the Teachings. The rare and valuable 

 peroxide of manganese was consumed in the 

 manufacture of chlorine and chloride of lime, 

 and the useless chloride of manganese was 

 formed in its place. This waste was remedied 

 by the invention of a process for getting rid of 

 the chloride. The price of soda continuing to 

 fall, the next remedy was sought in treating 

 new ores which would furnish other remunera- 

 tive merchantable products. For iron pyrites 

 was substituted copper pyrites, in which pre- 

 cious metals are often accompaniments, and 

 from which profit might be derived through 

 the silver or gold that could be extracted from 

 their cinders. 



Mr. A. McDonald Graham prepares a com- 

 position for precipitating sewage by heating a 

 mixture of iron pyrites and binoxide of manga- 

 nese in close contact with air, whereby a sul- 

 phate of manganese and iron is obtained. In 

 operating on the sewage, the sulphates of iron 

 and manganese may be used with a certain pro- 

 portion of clay. Charcoal may also be associat- 

 ed with it if the sewage is much discolored, and 

 lime if it is acid; but generally the sewage will 

 be found sufficiently alkaline. In order to con- 

 vert the sewage-mud into a useful precipitant, 

 it must first be dried. Formerly the drying 

 process was attended with much difficulty and 

 expense ; but as the nature of the product to 

 be treated has become better understood, the 

 drying difficulty has been to a great extent sur- 

 mounted. It is found by experience that after 

 such a precipitating medium as alumina, iron, 

 or manganese has passed through the sewage, 

 it acquires the property of spontaneous heating 

 when mixed with organic matter. If, there- 

 fore, the mud obtained by the use of such pre- 

 cipitants on the sewage be deprived of super- 

 fluous water by means of a filter-press and 

 placed in heaps in a sheltered situation, a natu- 

 ral heating takes place, after which the mud 

 becomes dry and friable and can be readily 

 brought into a fine state of division. It should 

 then be furnaced with sufficient iron pyrites 

 to reconvert the iron and manganese into sul- 

 phates. 



Richard Meyer makes use of the microscope 

 in the examination of printed cotton goods to 

 ascertain whether the dye as such has been 

 produced inside of the fiber, or whether it has 

 been employed already formed and fixed by 

 means of albumen. If the fabric is macerated, 

 using a needle so that the single fibers can be 

 isolated, these will appear equally colored 

 throughout their entire mass if they have been 

 colored by a dissolved dye. The characteristic 

 form of the fiber remains unaltered, and it can 



