434 Miscellaneous Intelligence, 



previously deprived of air by ebullition. The f2;aseous body to be 

 tested is then to be passed into this jar ; if there be only lOOOdth 

 of oxygen present, it will be indicated by the ocraceous colour com- 

 municated to the .oxide of iron. — Kastners Archiv. Bull. Univ.y 

 A. X. 157. 



9. Combinattons of the Nitrous Oxide with Salifiable Bases. — The 

 substances left "by the partial decomposition of certain nitrates by 

 heat are considered by M. Hess as compounds of the nitrous oxide 

 or oxide of azote with the bases of the salts used. The compound 

 with potashi for instance, may be obtained by hedting nitrate of 

 potash to redness in a silver crucible, so long as it disengages 

 oxygen : when no more smoke rises from the crucible, and an in- 

 flamed body is extinguished upon immersion in its atmosphere, 

 then the decomposition has been carried far enough, and the fused 

 salt is to be poured out upon a plate of iron. When cold, its frac- 

 ture is radiated; it is qn.altered in the air, sqluble in cold water, 

 more so in boiling water, and crystalhzes on cooling. It so much 

 resembles nitrate of potash as not to be distinguishable in ap- 

 pearance. It is insoluble in alcohol ; fuses with the readiness of 

 nitre. It includes no water of crystallization, but contains per cent. 

 61.14 potash, and. 38.80 oxide of azote. 



The 50€?a • compound is prepared in a similar manner from the 

 nitrate of soda, but more readily. It crystallizes in rhomboids, in- 

 soluble in alcohol. The water included in the crystals cannot be 

 dissipated by hep-t. It contains 44.52 of soda, 42.67 of oxide of 

 azote, and 12^1. of water per cent. 



The 6«ryto compound is to be obtained in the same manner, but 

 the heat mtist not be intense, nor of long continuance ; the mass is 

 then to be, dissolved in water, evaporated and, crystallized, after 

 which it should be purified by a second erystallization from the 

 carbonate of baryta mixed with it. It is constituted of 61.47 baryta ; 

 24.07 oxide of azote ^ 14.46 of water. The water of crystaUization 

 cannot be separafed by' heat. 



The combination with lime, obtained in the same way, gave per 

 cent. Hme 27.58 ; oxide of azote 28.94, and water 43.48. 



The compound with silver was procured by decomposing the 

 baryta compound by sulphate of silver. During evaporation the 

 liquid deposited long straw-coloured needles, which became black 

 by sun-light: being slightly heated in a glass tube, they were de- 

 composed, yielding metalHc silver and nitrous acid. This compound 

 was difficult to obtain. — Ann. der Phys. und Chimie, 1828, p. 257. 



10. Decomposition of Boracic Acid by Hydrogen. — The opinion 

 that boracic acid is not decomposed by hydrogen is not quite cor- 

 rect. M. Varvinski passed hydrogen through a porcelain tube 

 heated to redness and containing boracic acid in scales. The result 

 W^ a brown vitrified boracic acid, which being acted upon by 



