444: Scientific Intelligence. 



much improved by the aluminium chloride treatment, as they are 

 thus saturated, and the resinous and asphaltic constituents are 

 eliminated. The aluminium chloride is recovered for further use, 

 best by distillation in an atmosphere of chlorine. — Jour. Indmt. 

 and Eng. Chem., vii, 737. h. l. w. 



2. Arsenious Oxide as an Alkalimetric Standard. — Alan W. 

 C. Menzies and F. 1ST. McCarthy have found that arsenious oxide 

 may be employed with accuracy, and without too complicated 

 manipulation, as a primary standard in alkalimetry. A good 

 quality of the oxide is purified by subliming once in a 6 X 1 inch 

 test tube which has been drawn down to one-fourth its bore at a 

 point about 2 inches from the closed end. The product is dried 

 by heating and bottled hot. To prepare 500 cc of T \ N. solution 

 a quantity of about 2-47 g. is weighed accurately in a 75 cc conical 

 flask. This is then treated with 5 C0 of pure, concentrated nitric 

 acid followed by 5 CC of water. Solution and oxidation are 

 effected by careful heating with a suitable trap attached to the 

 mouth of the flask to avoid loss by spattering, and 5 CC more of 

 concentrated nitric acid are added. The nitric acid is now 

 removed by evaporation, best by the aid of a jet of cotton-filtered, 

 ammonia-free air. The heating can go as high as 230° C, but it 

 is necessary to take up the residue in water and evaporate to dry- 

 ness twice in order to remove all of the nitric acid. It is then 

 only necessary to dilute to the required weight or volume of 

 solution. To a measured quantity of about 30 or 40 cc of the 

 solution are added phenol-phthalein as indicator and 3 or 4 CC of 

 saturated barium chloride solution. The alkali is then run in 

 until the amorphous white precipitate, formed locally, is rather 

 slow in re-dissolving, then the glass surface beneath the liquid is 

 scratched until the lustrous, silky, crystalline precipitate of 

 BaHAs0 4 begins to form, when the titration is completed in the 

 usual way. Carbonate-free sodium hydroxide, containing barium 

 hydroxide, may be used as the alkaline solution. The authors 

 compared this method of standardization with several other 

 accurate methods and obtained practically identical results in all 

 cases. — Jour. Amer. Chem. Soc, xxxvii, 2021. h. l. w. 



3. A JVew Method for the Qualitative Separation and Detec- 

 tion of Arsenic, Antimony and Tin. — F. L. Hahn has proposed 

 the following method, which he considers preferable in the hands 

 of students to the methods usually employed. Starting with the 

 mixture of the higher sulphides of the three elements mixed with 

 much sulphur, this is extracted in the cold with a 5 per cent solu- 

 tion of Na 2 S. The sulphides go into solution very easily, while 

 the sulphur remains behind. To the filtered liquid 10 per cent 

 NaOH is added to the extent of about double the Na 2 S solution 

 used. Then an excess of hj^drogen peroxide is added and the 

 mixture is boiled. In the presence of antimony a crystalline 

 precipitate of Na a H 2 Sb a 7 soon begins to separate, and the pre- 

 oipitation of the antimony is made complete by cooling and add- 

 ing about ^ the volume of alcohol. The precipitate is then 



