458 EXPERIMENT STATION RECORD. 



carbonate of ammonia' to remove the lime and magnesia, and allow to 

 stand 12 hours. Filter and wash with 10 to 15 cc. of the precipitant 

 and evaporate to dryness in a platinum dish with the addition of a 

 very little concentrated sul])huric acid, keeping the dish carefully cov- 

 ered during the early stages of the evaporation. Drive off the ammo- 

 nia salts at a red heat, take up in hot water, filter into a porcelain 

 dish, add the necessary amount of platinum chlorid- and a drop of 

 dilute hydrochloric acid, and evaporate on a boiling water bath to a 

 sirupy consistency. Cool, add 20 to 25 cc. of a mixture of alcohol and 

 ether (2 to 1), grind up the crystals and allow to stand ]5 minutes, and 

 filter through a porcelain crucible with perforated bottom. Pass a 

 stream of purified hydrogen over the double salt in the crucible, at the 

 same time heating gently, until the salt is reduced (with the device 

 described this usually requires 10 to 15 minutes). Cool, wash out the 

 sodium sulphate and potassium chlorid produced with hot water, dry, 

 ignite, and weigh the metallic platinum. 



The solution of organic materials is prepared by digesting according 

 to the Kjeldahl method, using 100 gm. of material, 100 to 125 cc. of 

 acid, and G to 7 gm. of mercury, in case of barnyard manure, making 

 up the final solution to 1 liter and using 50 cc. for the determination of 

 potash. Neutralize this with ammonia, add 25 cc. of neutral ammo- 

 nium carbonate, let stand over night, and make up to 200 cc. Evapo- 

 rate 100 cc. of this solution to dryness and drive off the ammonium 

 compounds. The latter can be safely and completely done by heating 

 for 3 to 4 hours over a small flame. The rest of the operation is 

 conducted as described above. 



In case of poudrette, feeding stuffs, etc., 20 gm. is used, and of milk 

 100 cc. Tests of the method on a variety of substances gave very 

 satisfactory results. 



A method for working up platinum refuse into platinum chlorid is 

 described in detail. 



The determination of phosphoric acid in medicinal -wines, F. 

 Glaser and K. MtiHLE {Chem. Ztg., 20 {1896), Ko. 75, p. 723).— ThQ 

 method proposed is as follows: Evaporate 100 cc. of wine in a 250 cc. 

 digestion flask to a sirupy consistency, cool, add 25 cc. concentrated 

 nitric acid, and warm gently until the reaction begins. This will go 

 on without further heating. When the evolution of gas has ceased 

 add 75 cc. of concentrated nitric acid and again warm gently. Evap- 

 orate nearly to dryness over a small flame, cool, add 10 cc. concentrated 

 sulphuric acid, and a drop of mercury, and heat until the solution is 

 light colored. Cool, fill the flask to the mark, and filter off' 100 cc. of 

 the solution, and determine the phosphoric acid in it. 



It is stated that only the Fresenius method in which the residue from 

 evaporation is carefully incinerated gives absolutely accurate results, 



' A process for preparing this reagent according to Finkener is described, 

 ■' That used is HiPtClo and not PtCl4. 



