232 Scientific Intelligence. 



250°, and consisting of another new compound having the com- 

 position (C 6 H 5 ) 3 Se 2 . C 6 H 4 C1. This last fraction is a red oil hav- 

 ing at 19*60 a density of 1-55. On standing it deposits yellow 

 crystals having a powerful odor, which on re-crystallization from 

 alcohol may be obtained in long rhombic prisms. This substance 

 is seleno-phenol (C 6 H 6 )SeH, analogous to thiophenol and mer- 

 captan ; and like these bodies its alcoholic solution reacts readily 

 with mercury and silver salts, the latter affording the compound 

 C ^ fie Ag.-^ Bull. Soc. Chem., Ill, ii, 788, Dec, 1889. o. f. b. 



3. On the Production of Sodium carbonate by the Electrolysis 

 of the Chloride. — A series of experiments by Fogh made at 

 Hempel's suggestion, showed that the difficulty in electrolyzing 

 metallic chlorides lay in the fact. that whenever the decomposition 

 products were readily soluble, they were in their turn decomposed 

 so soon as they reached a certain limit. If, however, the products 

 of electrolysis were difficultly. soluble, no such secondary action 

 took place and all the electric energy was expended on the 

 primary decomposition. Inasmuch as sodium carbonate and 

 hydro-sodium carbonate are difficultly soluble in a saturated solu- 

 tion of sodium chloride, Hempel concluded that by the introduc- 

 tion of carbon dioxide into the apparatus, salt could be directly 

 converted by the current into sodium carbonate and chlorine. 

 The apparatus which he has contrived for this purpose consists of 

 a circular kathode of perforated iron and a similar anode of 

 carbon, having between them a disk of asbestus paper. Outside 

 of each electrode is a ring of porcelain and a disk of glass form- 

 ing chambers for containing the materials, a glass tube carrying 

 carbon dioxide into the kathode chamber and another carrying 

 the chlorine away from the chamber containing the anode. A 

 lateral tube of considerable size permits the salt to be fed con- 

 tinuously to the anode, the water removed by the crystallized car- 

 bonate being replaced through it. An electromotive force of 

 3*2 volts is required to decompose the salt and one of 2*5 volts to 

 overcome the polarization of the plates ; though if both plates are 

 of carbon, the counter electromotive force of polarization is absent. 

 With a current of 1*73 amperes, 0'930 gram of chlorine is pro- 

 duced per hour. So that by the use of a dynamo, 64*5 grams of 

 chlorine and 259*8 of sodium carbonate Na 2 CO 3 (H 2 O) ]0 would be 

 produced per horse-power per hour. The same general idea is the 

 basis of a patent taken by Marx since the author began his ex- 

 periments ; but the mechanical arrangements of Marx's apparatus 

 were bad and the results were not satisfactory. — Ber. Berl. Chem. 

 Ges., xxii, 2475, Oct., 1889. g. f. b. 



4. Barium cobaltite. — Rousseau has shown that cobalt dioxide 

 possesses acidic properties. If barium chloride mixed "with 

 barium oxide be fused in a platinum crucible, and cobaltic oxide 

 Co 2 3 be added in successive small portions, a crust of barium 

 cobaltite forms on the surface. After cooling and washing with 

 hot water and acetic acid, brilliant black hexagonal lamina? are 

 obtained having the composition BaCo 2 6 , which are soluble 



