1867.] Chemistry. 241 



between antimoniuretted and arseniuretted hydrogen. When the 

 former, he says, is passed over fragments of caustic potash, it is 

 decomposed, and the potash becomes covered with a brilliant 

 coating of antimony. Arseniuretted hydrogen is not attacked by 

 potash and passes on unchanged. 



A paper by Stahlschinidt " On the Beducing Action of Zinc,"* 

 shows that nitrate of potash boiled with finely-divided zinc is 

 reduced to nitrite. The following is the process adopted : — A 

 saturated solution cf nitrate of potash is gently heated with one- 

 tenth its volume of ammonia, and some zinc in powder. At from 

 30 J to 40° C. the action proceeds briskly, and it maybe necessary to 

 moderate it by the application of cold. In the course of half-an- 

 hour the nitrate is so far reduced that the addition of twice its 

 volume of alcohol to some of the solution causes no precipitate. 

 There will be a little free potash and some oxide of zinc in the 

 solution. The former must be neutralized with nitric acid, and the 

 oxide of zinc removed. The nitrate can then be separated from 

 nitrite by crystallization. 



"We may say here that we have recently met with an alloy of 

 zinc, with about 12 per cent, of iron, which is easily reduced to a 

 fine powder, and will answer the purpose of this and other 

 experiments of the kind. 



Dr. E. Wagnerf proposes to reduce the cost of the production 

 of nitric acid, by reverting to a modification of the old process for 

 making aqua fortis. He finds that hydrated alumina, when heated 

 with nitrate of soda, causes the evolution of nitric, and some hypo- 

 nitric acid, and forms aluminate of soda. This, when treated with 

 carbonic acid, gives carbonate of soda ; and the hydrate of alumina 

 is reproduced for future operations. This would seem to be a useful 

 process. Silica (fine sand for example) also decomposes nitrate of 

 soda, even at a lower temperature than the hydrated alumina. In this 

 instance, silicate of soda, another marketable product, is obtained. 



Fichter, of Berlin, recommends the use of baryta, in preference 

 to soda or lime, in the manufacture of pure acetic acid, from crude 

 wood vinegar. The acetate of baryta withstands the torrefaction, 

 necessary to get rid of the empyreumatic matters, much better than 

 the acetates of lime or soda, and there is consequently a much 

 smaller loss of acid. 



One other technological matter deserves notice. Bolley has 

 found that hypochlorite of magnesia bleaches much faster than the 

 corresponding lime compound. Magnesia, he shows, is much the 

 weaker base, and more readily parts with its chlorine. In the case 

 of straw, he states, the hypochlorite of magnesia has a special 

 advantage. 



* Poggendorff s 'Annalen,' 128, 466. 

 f Dinger's ' Polytech. .Tmirn.,' 1 Jan. heft. 

 VOL. IV. B 



