2S6 Scientific Intelligence. 



be produced, and this possesses the remarkable propert^y of spon- 

 taneously polymerizing at a slightly higlier temperature with 

 explosive violence and forming a brown powder. — Chem. JVeios, 

 cii, 49 and 61. h. l. \v. 



2. T/ie Action of Carbon- Tetrachloride iipon heated Anhy- 

 drides, Oxides, and several Minerals. — Tiiis metliod of simul- 

 taneously reducing oxides and forming chlorides has been the 

 subject of many investigations for more than twenty years. 

 Camboulives, however, has recently studied the process syste- 

 matically, using a large number of oxides. The substances were 

 placed in a boat within a tube of Bohemian glass, heated by 

 means of a combustion-furnace, and vapor of carbon tetrachlor- 

 ide was passed through the tube. The temperature at which the 

 reaction commenced was found by the nse of a Le Chatelier 

 thermo-electric couple placed witliin the tube near the boat. 

 Care was taken to use as far as possible substances of the same 

 degree of pulverization, but it was impossible to obtain the same 

 porosity in all cases. For instance, the alumina prepared by the 

 ignition of ammonium alum was readily attacked, while natural 

 corundum was acted upon slowly and incompletely. 



It was found that the temperatures of reaction are usually low, 

 varying fromi 215° C. (with niobic anhydride) to 580° C. (with 

 chromic oxide). The product in almost all cases is a chloride, 

 for among the thirty oxides that were attacked only the oxides 

 of niobium and thorium gave oxychloride, which in both cases 

 was mixed with chloride. The process is well suited not only for 

 the formation, but for the practical preparation of many anhy- 

 drous chlorides, especially those of the rare earth metals, chro- 

 mium, nickel, vanadium, titanium, zirconium, beryllium, cadmium 

 and cobalt. 



Two oxides, silica and boracic anhydride, were found to be 

 unattacked by the operation under consideration, but certain 

 silicates are attacked to a degree apparently inversely proportional 

 to their richness in silica, and the hydrous silicates are com- 

 pletely transformed into chlorides. Hence a mixture of clay and 

 sand may be analj'zed in this way, since the silicate of alumina 

 forms the volatile chlorides of silicon and aluminium, and the 

 sand is left behind. — Bidletin, IV, vii, 616. h, l. w. 



3. A New Method for Sejjarating Tin and Antimony. — In 

 connection with an investigation in which a number of acid fluo- 

 rides were prepared, Fischer and Thiele have observed that 

 antimonic and stannic acid fluorides are different in their behav- 

 ior with hydrogen sulphide. A solution containing tin and anti- 

 mony is first oxidized, so that the metals are in the stannic and 

 antimonic conditions ; then the sulphides are precipitated with 

 hj^drogen sulphide and dissolved in hydrofluoric acid. In this 

 solution hydrogen sulphide precipitates reddish brown antimonic 

 sulphide, leaving the tin in solution. By evaporating this solu- 

 tion in a platinum dish with sulphuric acid until the hydrofluoric 

 acid has been expelled, and taking up the residue with water, 



