CHEMISTRY. 443 



tallizes out. For the new acid tbe uaine disiili)li()p('i sulphuric is i)ro- 

 posed. (Compt. Kend., cvi, 851 aud 1854.) 



Tellurium. — According' to Berthelot and Fabre the transformation of 

 amorphous tellurium into the crystalline variety is attended by an ab- 

 sorption of heat. In this j)articular it is the opposite of selenium. 

 Fabre finds that in its different modifications tellurium has sensibly 

 the same specific heat. Telluride of magnesium is easily prepared by 

 lieating magnesium in dry hydrogen, and passing over it an excess of 

 tellurium vapor. It is a white, flaky substance, which, treated with 

 acidulated water, yields telluretted hydrogen, and the latter gas is so 

 unstable as to decompose immediately in contact with moist air. Its 

 heat of formation is negative. A number of metallic tellurides were 

 prepared and studied by Fabre thermochemically. Their heats of 

 formation were all positive, but less than in the case of the correspond- 

 ing selenidcs. (Ann. Chim. Phys. (0), xiv, 93, 110.) 



Solution of iron in caustic soda. — When a strong current of air is 

 foiced into a hot, concentrated solution of caustic soda contained in an 

 iron vessel, or in which finely divided ferric hydroxide is suspended, 

 noticeable qudntities of iron are dissolved without coloration. At 

 ordinary temperatures the liquid remains clear and colorless for sev- 

 eral days, but ultimately becomes turbid and discolored, depositing fer- 

 ric hydroxide. This color or turbidity disappears upon heating. Zir- 

 nite, who describes the phenomenon, attributes it to the possible for- 

 mation of a sodium i)erferrate, ]S^aFe04. (Journ. Chem. Hoc, lvi, 105 ; 

 from Chem. Zeitung, xii, 355.) 



Luieocohalt liermangaiiate. — This salt, with several of its derivatives 

 intermediate between it and the chloride or bromide of luteocobalt, is 

 remarkable for being violently explosive, both upon heating and by 

 percussion. It forms many highly crystalline double salts of consider- 

 able stability. (T. Klobb, Ann. Chim. Phys. ((>), xii, 5.) 



Electrolytic precipitation of copper. — According to Soret, dilute solu- 

 tions of coppei', except with verj- weak currents, yield a spongy precipi- 

 tate of metal. The nature of the dei)0sit depends not only on the in- 

 tensity of the electric current and on the concentration of the solution, 

 but also on the proportion of free acid which may be present. The 

 electrolytic copper always contains hydrogen, its amount depending 

 upon the temperature of the solution and its acidity. That hydrogen 

 is simply occluded, not combined; and it sometimes contains traces of 

 carbonic anhydride and carbonic oxide. (Compt. Kend., cvii, 733.) 



Neir jilotinum bases. — Dr. H. Alexander describes a number of com- 

 pounds, analogous to the i)latosamines, in which hydroxylamine replaces 

 ammonia. The platodioxamine, of which the chloride, PtCl>.4NH30, 

 corresponds to the chloride of Eeiset's base, forms a large series of selts, 

 in which alkalies precipitate an insoluble hydroxide, Pt(On)2.4:NIl30. 

 In this reaction the hydroxylamine base differs from all the other plati- 

 num bases so far known. (Ann. Chem., CCXLVI, 239.) 



