CHEMISTRY. 865 



" (3) Somewhat lower and more accurate results are obtained by using a blank 

 made by employing a dilute solution of a phosphate, whifh is added to each deter- 

 mination. This blank, previously determined, being substracted from the final 

 result. 



" (4) Accurate results, agreeing with those obtained by the use of the blank, are 

 obtained by redissolving the maguesium jiyrophosphate and reprecipitating. 



" (5) Five minutes' digestion at 65° C. seems to be sufficient for the complete pre- 

 cipitation of phosphoric acid by molybdic solution." — r. h. loughridge. 



Ths detennination of pho3phoric acid, H. Pembbrton, Jr. 

 (Jour. Amer. Chem. Sac, 17 {1895), No. 3, pp. 178-181).— The author 

 <-jilIs attention to several points in his method (E. S. K., 5, p. 444). In 

 preparing the standard alkali the indicator used should be phenol- 

 phtlialein and not methyl orange, as the latter is aftected by the alumina 

 usually contained in potassium hydroxid. In heating the solution it 

 should be brought to a full boil. It will then take care of itself and 

 does not need any definite temperature for proper precii)itation. In 

 precipitating, the aqueous molybdate should be added slowly, stirring 

 frequently, thus obtaining a purer precipitate. — J. P. street. 



The determination of potash in manures, W. E. Garrigues 

 (Jour. Amer. Chem. Soc, 17 {1895), No. 1, pp. 47-51).— Wo\± 10 gm. of 

 the sample into a paste with concentrated sulphuric acid in a platinum 

 dish. Ignite, raising the heat gradually until the residue is white, or 

 red if iron be present. Grind the residue in a mortar to a fine powder, 

 add a little hot water, and triturate the mass for a few minutes. Wash 

 into a 500 cc. flask and boil with 250 cc. of water for 30 minutes, and 

 tben run in a 10 per cent solution of barium chlorid, 5 cc. at a time, 

 boiling after each addition, until no further precipitation is visible. 

 Add sodium carbonate until a faint permanent rose color is obtained 

 with phenolphthalein. Boil for a minute, cool, and fill to the mark. 

 Filter, add hydrochloric acid in slight excess to 50 cc. in a porcelain 

 dish, and evaporate on a water bath with platinic chlorid. Wash the 

 precipitate with alcohol (sp. gr. 0.848), dry at 100'=^ C, and weigh. For 

 potash salts, the ignition with sulphuric acid is omitted. 



The sulphuric acid must be added cautiously to prevent loss from 

 the violent reaction, when chlorids and nitrates are present. The 

 ignited mass must be pulverized very finely, to prevent the occlusion 

 of potash by the calcium sulphate. An excess of sodium carbonate 

 must be avoided, as double decomposition may take place. 



While the method does not, in common with those now in use, return 

 quite all the potash, it is claimed that it is no less accurate, and gives 

 less discordant results than the Lindo-Gladding, l)esides being more 

 satisfactory to work and quicker. One filtration and evaporation only 

 are entailed, but a greater quantity of platinic chlorid is required. — 



J. P. STREET. 



The addition of calcium chlorid to the solution of a fertilizer in 

 the determination of potash, K. de Roode {Jour. Amer. Chem. Soc.y 

 17 {1895), No. l,p. 46). — Experiments made by the author indicate that 



