CHEMICAL SCIENCE. 213 



of soda; temperature about 160 C. Also, from chloride of manganese 

 and carbonate of lime ; temperature between 140 and 170 C., for 

 twelve to forty-eight hours. 



Carbonate of zinc from a process like that for carbonate of iron. 

 Cqmptes Rendus, June, 1849. 



METHOD OF OBTAINING CRYSTALLINE COMBINATIONS BY HEAT, 

 AND OF REPRODUCING THEREBY VARIOUS MINERAL SPECIES. 



IT is known that borax, boracic acid, phosphoric acid, and the alka- 

 line phosphates, dissolve metallic oxides with ease, at a certain tem- 

 perature, and abandon them at a much higher temperature by virtue 

 of their volatility. These bodies enjoy, therefore, in regard to the 

 oxides which they hold in solution, the function which water pos- 

 sesses at the ordinary temperature, or at temperatures more elevated 

 in relation to bodies held in solution by it, that very often on evap- 

 orating it leaves such bodies in a crystalline condition. This simple 

 principle has led M. Ebelmen to a method which will enrich chemis- 

 try, by the dry method, with a great number of novel combinations, 

 and which will establish the most intimate connection between miner- 

 alogy and chemistry. On mingling together, for example, alumina 

 and magnesia in a little larger proportion than they exist in spinel, 

 with a portion of fused boracic acid, and exposing the mixture to the 

 most elevated temperature of a porcelain furnace, octahedrons are ob- 

 tained which possess the composition and properties of spinel. These 

 crystals are rose-red or blue according as the oxide of chrome or of 

 cobalt is used. M. Ebelmen has obtained in this way chrysoberyl, 

 and many other aluminates. He has prepared many varieties of 

 chrome iron, which all present regular octahedrons with the usual min- 

 eralogical characters, and has also obtained, by the aid of this process, 

 the emerald and peridot crystallized. Boracic acid is too volatile 

 to aid in crystallizing alumina, and in this case he employed borax. 

 By the addition of a little oxide of chrome, crystals of red ruby are 

 obtained, having the formula of transparent corundum. Comptes 

 Rendus. 



ASPARAGINE. 



M. DUMAS has communicated to the Paris Academy of Sciences an 

 important paper by M. Dessaignes on asparagine, which he finds existing 

 in the young shoots of the plants that compose the family Leguminacece. 

 He appears to suppose it to be the legumine which is in the act of ger- 

 mination changed into asparagine. London Athenaum, Feb. 3. . 



NEW METHOD OF COPYING ENGRAVINGS. 



AT a meeting of the Royal Society in May, M. Niepce exhibited a 

 drawing produced by the following ingenious process. An engraving 

 is placed in a box containing iodine, at such a temperature that a small 

 portion is vaporized. The ink of the engraving condenses a much 



