4TS Scientific Intelligence. 



white heat. After the reaction had ceased, a transverse section 

 showed that surrounding the carbon rod, was (1) a zone of adher- 

 ing graphite, (2) a zone of crystallized silicon carbide, (3) a zone 

 of amorphous silicon carbide, (4) a zone containing pockets of 

 fibrous material, (5) a zone of the original mixture only slightly 

 altered and, (6) a hard external layer consisting almost entirely 

 of salt. The graphite had all the properties of the natural min- 

 eral, but had the crystalline form of the silicon carbide ; indicat- 

 ing that the latter is first formed and then loses its silicon by 

 volatilization. The outer portion of this graphite zone gave 

 33*71 per cent of variously colored crystals containing 30*49 per 

 cent of silicon and 68*26 of carbon. The second zone constituted 

 the chief product of the reaction. On breaking up the mass in a 

 mortar, the separate crystals were obtained, bluish or yellowish- 

 green in color, and varying in size from microscopic dimensions 

 to several millimeters in diameter. To purify it, it was heated to 

 dull redness in oxygen, boiled with potash solution, washed, 

 digested with hydrochloric acid and finally treated with hydro- 

 fluoric acid. It then has the composition SiC, and a density of 

 3*22 at 15°. Under the name of carborundum it has come into 

 use in the arts to replace emery. — Zeit. Anorg. Chem., v, 105, 

 October 1893. G. f. b. 



6. On Antimony- Blue. — According to Sebor, antimony-blue 

 may be prepared by dissolving antimony sulphide in concentrated 

 hydrochloric acid, and, after filtering, adding to the boiling 

 liquid a concentrated solution of potassium ferrocyanide and 

 some potassium chlorate or nitric acid. The precipitate is dried 

 at 100°. Another antimony-blue may be obtained by mixing- 

 antimony chloride and potassium ferrocyanide and adding a large 

 quantity of water. When prepared in this way however, it con- 

 tains some basic antimony chloride. A sample of pure antimony- 

 blue yielded on analysis Fe 30*28, Sb 2*422, H 2 5*828, CI 0*712, 

 O 0*323, and Cy 60*435 per cent. Antimony-blue is insoluble in 

 cold hydrochloric, sulphuric and nitric acids, and yields hydrogen 

 cyanide when boiled with hydrochloric or sulphuric acid. Warm 

 dilute sodium and potassium hydroxides attack it, and nitric acid 

 on heating converts it into a grayish-green compound. Unlike 

 Prussian blue it is not soluble in a solution of an oxalate or a 

 tartrate. — Chem. Gentr., ii, 318, 1893 ; J. Chem. Soc, lxvi, i, 3, 

 Jan. 1894. G. e. b. 



7. On the Nitro-metals. — The researches of Sabatier and 

 Senderens upon the nitro-metals have been continued and they 

 now report the discovery of nitro -cobalt, nitro-nickel and nitro- 

 iron. Nitro-cobalt is best prepared from cobalt reduced at a low 

 temperature, by passing over it nitrogen peroxide suitably diluted 

 with nitrogen. Black nitro-cobalt CO„NO„ is thus produced, 

 upon which water acts vigorously, but gives less nitrogen dioxide 

 than nitro-copper ; producing a solution of cobalt nitrate, con- 

 taining very little nitrite. Heated in nitrogen nitrous fumes are 

 evolved and then decomposition takes place with almost explosive 



