156 Intelligence and Miscellaneous Articles. 



To prove that it contained no hydrogen, the black powder was 

 mixed with peroxide of copper, and heated as in vegetable analyses ; 

 but the quantity of water obtained was such as to show that it could 

 not contain -j oVvth of its weight of hydrogen, and it is most pro- 

 bable that it did not contain any. On account of the difficulty of dry- 

 ing, the water was undoubtedly hygrometric. These experiments 

 appear sufficient to prove that the supposed hydruret of platina is 

 merely an alloy of iron and platina. 



Descotils obtained from an alloy of platina and zinc, by means 

 of dilute sulphuric acid, a black powder, which inflamed below a 

 red heat. M. Boussingault found that it contained 31 per cent, of 

 zinc, and its weight after combustion increased like that of the alloy 

 of iron and platina. M. Boussingault proposes to examine, at a future 

 opportunity, the black scales which Davy obtained by treating an 

 alloy of platina and potassium with water, and which he considered 

 as a hydruret of platina. — Ann. de Chim, et de Phys., torn. liii. p. 44- 1 . 



BORATES OF MAGNESIA. BY M. WOHLER. 



The boracite is a well known crystallized mineral, composed of 

 boracic acid and magnesia. When solutions of borate of soda and 

 borate of magnesia are mixed, no precipitation takes place until the 

 mixture is heated, and then an abundant white precipitate is formed, 

 which redissolves as the solution cools. 



A solution in which the crystals had redissolved was exposed for 

 several months to a temperature below 32° of Fahr. During this 

 exposure, fine radiated acicular crystals were formed, some of them 

 half an inch long • they were so slender that it was not possible to 

 determine their crystalline form. These crystals are transparent, 

 brilliant, hard and brittle, and perfectly insoluble in water, either 

 cold or hot. Muriatic acid when hot decomposed these crystals, 

 boracic acid being deposited on cooling ; when heated they became 

 opake and lost water. By analysis this salt yielded 



Boracic acid 25* 



Magnesia 16-67 



Water 58-40 



10007 

 The boracic acid and magnesia are in the same proportion as in 

 boracite. In the case of this salt we have additional examples of the 

 endless variety of symbols now inflicted upon the chemist. In the 



Ann. de Chimie et de Phys. it is represented by Mg B* + 16 H, 

 while in the Journal de Chimie Medicate we have (2 (Mgo)-f Tfo r > 

 + 16 H 2 o), and yet both writers agree in considering it as similar to 

 boracite combined with 16 atoms of water. Both differ from Berzelius. 



From the solution which yielded these crystals there afterwards 

 separated abundance of large brilliant, hard, transparent crystals 

 in the form of oblique rhombic prisms. 



This salt was found to be a double borate of soda and magnesia: 

 when heated it swelled, and lost 525 per cent, of water of crystalliza- 

 tion. The calcined residue redissolved in water, but so slowly that 



