Chemistry and Physics, 301 



of ferric hydroxide produced by hydrolysis upon boiling solu- 

 tions containing but little free sulphuric acid and producing a 

 brown color practically complementary to the violet one and thus 

 hiding it. — Jour. Chem. Soc., 119, 1944. H. l. w. 



3. The Per sulphides of Hydrogen. — James H. Walton and 

 Llewellyn B. Parsons, of the University of Wisconsin, have 

 made an interesting study of hydrogen disulphide, H 2 S 2 , and the 

 tri-sulphide, H 2 S 3 , which are constituents of the oily liquid pro- 

 duced by the action of hydrochloric acid upon alkali or alkali- 

 earth polysulphides. The existence of these two compounds had 

 been established, so that the results of the present extensive inves- 

 tigation have been improvements in the method for the prepara- 

 tion of the pure compounds and a more extended knowledge of 

 their properties and reactions. Only a few of the results can be 

 referred to here. 



It was found that while hydrochloric acid gives the well- 

 known yellow oily liquid with sodium poly sulphide solution, the 

 other common acids, acetic, phosphoric and sulphuric acids, do 

 not give any of the oil, but a complete decomposition into hydro- 

 gen sulphide and sulphur. It was found that the crude oil could 

 be dried most satisfactorily by the use of phosphorus pentoxide 

 which has no action upon it. The crude oil upon analysis gave 

 results corresponding closely to the formula H 2 S 5 , but it is 

 believed to be* really a solution of sulphur in the sulphides of 

 hydrogen. The nearly pure disulphide and trisulphide of hydro- 

 gen were obtained by a single distillation under low pressure by 

 the use of two successive receivers, the first cooled by running 

 water, the second by ice and salt. Quartz vessels were used for 

 the distillation as well as for containers of the persulphides, since 

 it was found that quartz decomposed them far less rapidly than 

 glass. A very satisfactory method was devised for the analysis 

 of the persulphides. It consisted in dissolving the sample in car- 

 bon disulphide, adding acetone which caused a catalytic decom- 

 position into hydrogen sulphide and sulphur, evaporating to dry- 

 ness at 90° and weighing the sulphur. — Jour. Amer. Chem. Soc, 

 43, 2539. h. l. w. 



4. A Separation of Germanium from Arsenic. — John H. 

 Muller, of the University of Pennsylvania, who has recently 

 determined the atomic weight of germanium and in connection 

 with that work has called attention to the difficulty of removing 

 the last traces of arsenic from germanium, has now solved this 

 problem very satisfactorily. 



The distillation process from aqueous hydrochloric acid in the 

 presence of chlorine, Avhich has been recommended, did not give 

 satisfactory results, as it was found that minute quantities of 

 arsenic passed into the distillate when the conditions were suita- 

 ble for volatilizing the germanium chloride, although this method 



