224 EXPERIMENT STATION RECORD. 



follows: Ten grams of the sample is transferred to a liter flask and 300 

 cc. of water, acidulated with 1 cc. dilute hydrochloric acid, added. The 

 contents are healed nearly to the boiling point, and after thorough stir- 

 ring, a very dilute solution of barium chloridis added in an exceedingly 

 fine stream, until all sulphuric acid is precipitated, and only a trace of 

 barium chlorid is found in excess. After cooling, the flask is filled to 

 the mark, and the contents mixed. Fifty cubic centimeters of the clear 

 solution is then measured into a porcelain or platinum dish, and 10 cc. 

 of platinum chlorid solution (equivalent to 1 gni. platinum) is added. 

 The liquid is evaporated on a water bath to a thin sirupy consistency, 

 taking care that the precipitate does not stick on the sides of the dish. 

 Ninety per cent alcohol is now added, and the dish left standing until 

 the potassium-platinum chlorid crystallized out has settled well. The 

 liquid is filtered with suction through a weighed asbestus filtering tube, 

 and the chlorid washed repeatedly with small quantities of alcohol 

 which are decanted on the filter. The washing is continued until the 

 alcohol is colorless, and the chlorid then transferred to the filtering 

 tube by means of alcohol, washed with ether, dried at 130° C, and 

 weighed. — f. w. woll. 



The separate determination of total alumina and total iron 

 oxid in phosphates, F. Lichtschlag (Chem. Ztg., 21 (1897), Wo. 28, 

 pp. 264, 2<j,5).— The method depends on the solubility of the aluminum 

 phosphate in caustic soda solution. Two grams of the pulverized phos- 

 phate is fused in a platinum crucible with about 8 gm. of sodium car 

 bonate. After complete fusion the mass is digested with hydrochloric 

 acid at 50 to 60° C. until dissolved, then neutralized with strong 

 sodium hydrate, heated almost to boiling, when 30 cc. of the 20 per 

 cent sodium hydrate is added, and the contents violently stirred and 

 digested for 15 minutes. After cooling and making up to 200 cc, 50 cc. 

 is filtered off for the determination of alumina. 



The precipitate on the filter, as it contains a part of the iron oxid, is 

 washed back into the flask with hydrochloric acid and the total iron 

 oxid in the flask, after reduction with zinc, is determined by titration 

 with potassium permanganate. 



The 50 cc. reserved for the determination of alumina, after acidulation 

 with hydrochloric acid, is evaporated to dryness in a dish, taken up 

 again with hydrochloric acid, and after adding hot water, is filtered 

 into a beaker. It is now heated to boiling, made slightly alkaline with 

 ammonia, and after allowing the precipitate to subside, filtered, aud 

 washed free from chlorids with hot water. The precipitate is ignited 

 and weighed as A1P0 4 . To insure a sufficiency of phosphoric acid 

 for the alumina, it is advisable to add a few drops of sodium phosphate 

 solution before precipitation with ammonia. — j. t. Anderson. 



A simple method for the determination of fat in separated 

 cream, M. Weibull (Chem. Ztg., 21 {1897), No. 34, pp. 333-335).— The 

 total solids of the cream are determined in the usual way and the content 



of fat calculated by means of the following formula: t=f+ ,. )0 x con- 

 stant, in which t= total solids, f= fat. and " constant "= per cent of fat-free 



