1917] AGRICULTURAL CHEMISTRY AGROTECHNY. 505 



It is indicated that the complete removal of ammonia should be tested with 

 Nessler's solution, and that the aeration should be run slowly or at half speed 

 for the first minute or two. 



The separation of lithium from the other alkali metals, S. Palkin {Jour. 

 Amer. Chem. Soc, S8 (1916), No. 11, pp. 2326-2332).— After some preliminary 

 experimentation the author devised a modified procedure, the essentials of 

 which are as follows : 



The dried mixed chlorids are dissolved in a definite minimum amount of 

 water, acidified with hydrochloric acid, and the major portion of the sodium and 

 potassium chlorids precipitated by the addition of absolute alcohol followed by 

 ether. The precipitated chlorids are filtered, the filtrate evaporated, the residue 

 taken up in absolute alcohol containing a drop of hydrochloric acid, and the 

 residual amount of sodium and potassium chlorids, which is usually very small, 

 is completely precipitated by the addition of ether. These chlorids are then 

 filtered through the same crucible as used for the first precipitate and the 

 residue washed with ether-alcohol mixture. The ether-alcohol solution of lithium 

 is evaporated on the steam bath, the residue taken up with a little water, and a 

 slight excess of sulphuric acid added. The solution is then transferred to a 

 weighed porcelain or platinum dish, evaporated to dryness, and the residue 

 gently ignited. 



The following optional method is also described : 



The ether-alcohol solution of the lithium is evaporated to dryness In the 

 steam bath and finally dried in an oven at 110° C. for from 15 to 20 minutes. The 

 residue is taken up in from 5 to 10 cc. of alcohol, warmed if necessary, and then 

 diluted with about 50 cc. of water. If a slight sediment remains the liquid is 

 filtered thiough a Gooch crucible and washed with water, a few drops of phenol- 

 phthalein are added to the filtrate, and the liquid titrated with tenth-normal 

 alkali. The chlorids are precipitated as the silver salt and from the weight of 

 the latter is subtracted the amount corresponding to the hydrochloric acid 

 determined in the titration. 



Method of extraction as affecting the determination of phosphoric acid in 

 soils, H. BLA.LE and W. L. Habtley (Jour. Indus, and Engin. Chem., 8 (1916"), 

 No. 11, pp. 1028, 1029). — Analytical data submitted show that the 2-hour diges- 

 tion with twice-normal nitric acid, as described by Brauer (E. S. R., 33, p. 110), 

 extracts as much phosphoric acid as the official 10-hour digestion with hydro- 

 chloric acid of .specific gravity 1.115 (E. S. R., 20, p. 512). 



Investigation of methods for the determination of the soil reaction, H. R. 

 Chbistensen (Tidsskr. Planteavl, 23 (1916), No. 1, pp. 1-83, figs. 4). — Various 

 qualitative and quantitative methods for determining the reaction of soils have 

 been investigated. 



The results indicate that a distinction between the true acidity and the base 

 absorption area of the soil must be made. The method of Hopkins, given in 

 Bulletin 73 of the Division of Chemistry (E. S. R., 14, p. 1045), and that of 

 Daikuhara (E. S. R., 31, p. 618), were found to yield reliable results in the 

 determination of soil acidity. The procedure of Baumann and Gully (E. S. R., 

 19, p. 1008) was found to yield more accurate results than that of Tacke and 

 Siichting (E. S. R., 19, p. 1009). 



No free acids were found in sphagnum turf. The use of litmus paper for 

 the qualitative determination of soil acidity is deemed unreliable. 



The difficulty of determining the true acidity of a calcareous soil is indicated 

 and briefly discussed. 



A bibliography of 83 references is included. 

 85476°— No. 6—17 2 



