196 Scientific Intelligence. 



compounds of silver, cadmium, tin, copper, mercury, lead, iron, 

 zinc, cobalt, nickel and aluminum. Some of these salts were 

 found to form additive compounds with piperidine, and in a few 

 cases with the other solvents, as lead nitrate with pyridine, 

 cuprous chloride and cadmium iodide with methyl sulphide and 

 mercuric iodide with ethyl sulphide. By means of solutions of 

 anthracene and diphenylaraine, the molecular constant was 

 obtained for each solvent, as follows: methyl sulphide 18*5, ethyl 

 sulphide 32*3, pyridine 30*07, piperidine 28*4, benzonitrile 36*55. 

 As a result most of the salts examined gave results which agreed 

 with the normal molecular mass. Thus aluminum chloride gave 

 figures agreeing with A1C1 3 , the results being analogous for 

 FeCl 3 . Cobaltous chloride and bromide, stannous chloride and 

 bromide, and lead nitrate are all monomolecular ; i. e., contain 

 bivalent metallic atoms. In the case of the cuprous salts how- 

 ever, anomalous results were obtained. Cuprous bromide in ethyl 

 sulphide, for example, gave results corresponding to a molecular 

 mass of 226, while in pyridine and in methyl sulphide, the value 

 obtained corresponded with the molecular mass 140. Cuprous 

 chloride gave in all solvents an elevation corresponding to 120 

 and cuprous cyanide one corresponding to the formula Cu 2 (CN) 2 . 

 Hence the normal cuprous molecules are represented by the 

 formula CuCl, etc. sometimes partially associated to Cu 2 Cl 2 . Since 

 this result may also be explained by dissociation of the more 

 complex molecules, conductivity determinations were made, the 

 results of which indicated the absence of metallic ions. The 

 silver haloids showed a similar tendency to polymerize, giving 

 double and even treble molecules; confirming the author's views 

 of the cuprous salts. — Zeitschr. Anorg. Che?n., xv, 1-41, May, 1897. 



G. F. B. 



7. On /Sodium Carbide. — The properties of sodium carbide 

 have been further studied by Matignon. It is a white solid of 

 density 1-575 grams at 15°, insoluble in all solvents. Though 

 endothermic it is not exploded by a shock or by friction. At 

 ordinary temperatures, it is unacted on by air or oxygen if dry, 

 but when heated gently it becomes incandescent and is converted 

 into carbonate. In chlorine it burns evolving carbon ; iodine 

 converts it into C 2 I 4 , fusing at 185°. Water decomposes it 

 violently, setting free carbon : but added very gradually converts 

 it into acetylene-sodium hydroxide. Sodium carbide burns in 

 hydrogen chloride, producing sodium chloride and evolving 

 hydrogen and carbon. But if suspended in ether, it is completely 

 converted into acetylene and sodium chloride. It becomes incan- 

 descent in C0 2 or S0 2 , liberating carbon. Carbon monoxide does 

 not act on it below 250°, nor hydrogen sulphide below 150°. 

 Nitrous and nitric oxides attack it, the former at 270°, the latter 

 at 150°, with incandescence, yielding carbon and sodium carbon- 

 ate. Mixtures with oxidizing agents are very sensitive to shock. 

 Alkyl iodides and bromides act on it at 180°, yielding symmetri- 

 cal acetylenes RC i CR. It is a much more active salt than calcium 

 carbide, and its reactions are almost always violent. — G. B., 

 cxxv, 1033-1035, December, 1897. g. f. b. 



