CHEMISTRY. 953 



1,000 cc. One liimdrod cubic centimeters of this solution, correspond- 

 ing- to 10 grn. of the original substance, is distilled for the determina- 

 tion of nitrogen. 



For the determination of ammoniacal nitrogen, 100 gni. of the manure 

 is shaken up with 4 or ."> times its weight of water in a wide-necked 

 liter Hask and allowed to stand several hours. The solution is then 

 made up to 1,000 cc. and 100 cc. is withdrawn for distillation of the 

 ammonia, which is set free by the addition of 2 to .'} gm. of calcined 

 magnesia. 



For the determination of nitric nitrogen, two methods were tested, 

 namely, the zinc-iron method and Pfeilfer's ' method. The first of these 

 methods gave (piite discordant results, in everj- case mu<;h lower than 

 those obtained by Pfeifter's method. The latter, however, is somewhat 

 complicated and time-consuming, and it is suggested that it may be 

 modified to advantage. Instead of using the Lintner pressure flask, 

 it is suggested that the material be heated in an oven in a sealed 

 potash glass tube. 



The total phosphoric acid is determined in 50 cc. of the Kjeldahl solu- 

 tion by neutralizing with ammonia until a permanent i)recipitate begins 

 to form and adding 50 cc. each of nitric acid (sp. gr. 1.2) and molybdic 

 solution ; the remainder of the operation being conducted in the usual 

 way. The water-soluble phosphoric acid is determined in the usual way 

 in an alitjuot of the solution prepared for the determination of ammo- 

 niacal nitrogen. 



The method of determining potash has already been described in the 

 Record.^ For the determination of dry matter 3,000 grams of the 

 manure is Aveighed out on a. balance capable of weighing 25 kilograms 

 and sensitive to 0.1 gram. The sample is spread out in thin layers and 

 dried in an air bath at a temperature of from 60 to 05°, the material 

 being stirred once after the first 2 or 3 hours. The drying is usually 

 (;ompleted after 48 hours, and the material is then spread out in dishes 

 and exposed to the air for 24 hours. This dry-air substance is then 

 ground ;ind 3 gin, taken for the determination of the absolute moisture. 



Analysis of limestone, F. Scheiding {Ghem. Zt<j., .21 {1897), Xo.8, 

 pp. 54, 55). — The author criticises a method recently described in this 

 journaP and proposes one which he claims to be more accurate and 

 simple. The hydrochloric acid solution is oxidized with bromin water 

 and the iron and aluminum precipitated with ammonium hydrate. The 

 jirecipitate is ignited, dissolved in hydrochloric acid, which is subse- 

 (piently almost completely removed by evaporation. The solution is 

 then nearly neutralized with ammonia, and when cold an e(|ual volume 

 of strong acetic acid is added, a solution of about 0.1 gm. of nitroso-/y- 

 naphthol in 30 cc. of hot 50 i)er cent acetic acid is stirred in, and the 

 solution allowed to stand for a few hours to insure the complete precipi- 



' Landw. Vers. Stat., 46 (189;")), p. 1 (E. S. M., 7, ]>!>. 209, 552). 

 •^ Ibid. ,47 (189(5), p. 97 (E.S. R., S, ]». 457). 

 ='Cheni. Ztg., 20 (1896), p. 1004. 



