504 Scientific Intelligence. 



tion of the free base with ammonium sulphide, a bright orange-red 

 precipitate is thrown down, very similar to antimony sulphide, 

 and stable at 0.° At the ordinary temperature, however, it soon 

 begins to decompose, evolving white clouds of vapor and yielding 

 a mobile oil. Analysis shows it to be the trisulphide (C G ET & ) 2 I. 

 S. S. S. I (C 6 H 6 )„, its decomposition products being iodobenzene 

 and phenyl-trisulphide. The normal sulphide (C f H 5 ) 2 1. S. I 

 (C 6 HJ 2 is precipitated from solutions of the base by sodium sul- 

 phide, as a bright yellow precipitate, decomposing at ordinary 

 temperatures into iodobenzene and phenyl-sulphide. Several 

 double chlorides, formed with the chlorides of mercury, gold and 

 platinum are also described. The free base is reduced by sodium 

 amalgam, one molecule decomposing into benzene, water and hy- 

 drogen iodide, the latter substance precipitating a second mole- 

 cule of the base as insoluble iodide. The solution of the free base 

 precipitates solutions of the salts of the heavy metals exactly as 

 ammonia and the fixed alkali hydroxides do. The physiological 

 action of the chloride has been studied by Gottlieb. It is found 

 to be very poisonous, its mode of action combining the charac- 

 teristics both of the salts of lead and thallium with those of am- 

 monia and the ammonium bases. — Ber. JBerl. Chem. Ges., xxvii, 

 1592, July, 1894. G. F. b. 



2. On an Anomaly in the Density of Nitrogen. — In a paper 

 to the Royal Society, Rayleigh has called attention to an anom- 

 aly which he has encountered in his attempts to determine the 

 density of nitrogen prepared by different methods. He had 

 already established the fact that this gas, prepared by Lupton's 

 method, i. e., by passing air mixed with ammonia through a red- 

 hot tube containing copper, is lighter by about one thousandth 

 part than nitrogen prepared in the usual manner, by passing air 

 alone over the red-hot copper. Moreover he observed that on 

 substituting oxygen for air in the former process, in which case the 

 whole of the nitrogen instead of only about one-seventh part, comes 

 from the ammonia, the discrepancy was increased to about one 

 half per cent. In explanation of this condition of things, it might 

 be assumed (l) on the one hand, that the heavier nitrogen con- 

 tained admixed oxygen, or (2) that on the other the lighter speci- 

 mens contained some gas lighter than nitrogen. The former 

 hypothesis would seem to be negatived by the large quantity of 

 oxygen required for the purpose as well as by the precautions 

 taken to get rid of all of the oxygen, using various methods. The 

 latter seems no less improbable, since the only gases involved 

 are water-vapor, ammonia and hydrogen ; the two former being 

 very readily removed, and the latter being certainly oxidized by 

 the copper-oxide. Accordingly, further experiments were made, 

 the niti'ogen being prepared by the reduction of nitrogen mon- 

 oxide or nitrogen dioxide, or by the ignition of ammonium 

 nitrate, the gas obtained being in all cases passed over pure iron 

 at a red heat, and carefully purified. In four experiments made 

 on nitrogen prepared from NO by reduction with hot iron, the 



