146 Scientific Intelligence. — Chemistry. 



water contained in a tin vessel into ice during their solution, he ulti- 

 mately gave the preference to a mixture of 4 ounces nitrate of am- 

 monia, 4 ounces sub-carbonate of soda, and 4 ounces of water. 

 This mixture, in three hours, produced ten ounces of ice ; whilst 

 with the mixture of sulphate of soda and muriatic acid, he obtained 

 ice only after seven hours. — Idem. 



4. Action of iron on ammonia. (Le Globe, Avril 14.) — M. Des- 

 pretz announced some time since, that when heated metals were sub- 

 jected to the action of ammoniacal gas, they underwent a considera- 

 ble change in their Aveight, in consequence of combining with some 

 part of the ammonia. He now states that the weight of iron is some- 

 times increased as much as 11.5 per cent, in such an experiment, in 

 consequence of the combination of nitrogen with it. If the temper- 

 ature applied be too high, the nitrogen is expelled, and the compound 

 destroyed. — (Quarterly Journal, Jvly to Sej)t. 1829. 



5. Effect of muriatic and sulphuric acid on hydro-cyanic acid. 

 (Annales de Chimie, XL, 441.) — It is well known that hydro-cyanic 

 acid may sometimes be preserved for years unaltered, and, at other 

 times, changes and undergoes decomposition in eight or ten days af- 

 ter its preparation.' ' Whilst searching for the causes which influenced 

 the spontaneous change of the acid, M. Kuhlman examined into the 

 action occasioned by mixing other acids with the hydro-cyanic com- 

 pound. A mixture of muriatic and prussic acid being made and set 

 aside, in twelve hours the bottle containing it was lined inside with 

 yellow cubical crystals ; some were less colored than others, and 

 those formed after a longer interval of time were colorless. The 

 fluid part remained limpid, but was diminished to one half. The 

 experiment was repeated with recently prepared prussic acid, mixed 

 with its bulk of muriatic acid. No yellow crystals were obtained, 

 but a large quantity of colorless ones, similar to those last obtained 

 with the former liquor. With the exception of the coloring matter 

 of the first crystals, (apparently depending upon the smaller quantity 

 of muriatic acid in that experiment,) they all appeared to consist of 

 muriate of ammonia only. No gas was evolved by the mixture and 

 action of the acid. 



Equal parts of sulphuric and prussic acids were then mixed, though 

 with some little difficulty. A slight elevation of temperature took 

 place; after two days, no crystals were formed, no color produced, 

 no gas evolved. Heat being then applied, a little prussic acid was 



