

CHEMICAL SCIENCE. 



ARTIFICIAL PRODUCTION OF MINERALS. 



ELIE DE BEAUMONT and DTJFRENOY, in a report presented to the 

 French Academy, April 1, state that M. Daubree, having observed 

 that the ores of tin are constantly accompanied by fluoric or boracic 

 minerals, particularly mica, topaz, tourmaline, &c., was induced to 

 believe that this circumstance was connected with the cause which 

 produced the formation of the ores, and that the tin was brought into 

 its beds in the state of fluoride, and there, undergoing a double de- 

 composition, produced oxide of tin and fluoric minerals. He there- 

 fore endeavoured to produce, artificially, oxide of tin, by processes sim- 

 ilar to the supposed ones of nature, making use, however, of the 

 chloride instead of the fluoride. By passing through a porcelain tube 

 heated to a white heat two currents, the one of the vapor of perchlo- 

 ride of tin, the other of steam, he obtained small crystals of the oxide 

 of tin while the hydrochloric acid escaped in the form of vapor. The 

 crystals were deposited upon the inside of the porcelain tube, not how- 

 ever throughout its whole length, but at the entrance, where the tem- 

 perature was hardly 300 C., while the hottest portion contained none 

 at all. At the end where the vapors escaped, the oxide of tin formed 

 an amorphous concrete mass. The crystals adhered very strongly to 

 the tube, insinuating themselves into the smallest interstices of the 

 porcelain. They are very brilliant, and almost always colorless; they 

 are infusible, and unattacked by acids, resembling in these particulars 

 natural oxide of tin, but differing from it in crystallization, as they 

 belong to the system of the right rhomboidal prism. Oxide of tin, 

 therefore, admits the same dimorphism as oxide of titanium, with 

 which it is isomorphous. These facts led M. Daubree to suppose that 

 he might also obtain crystals of oxide of titanium, in which endeavour 

 he was successful, having produced crystals of Brookite. Chloride 

 of silicium gave also by decomposition small crystals of quartz.* 



* See Annual of Scientific Discovery, 1850 ; p. 212. 



