AGRICULTURAL CHEMISTRY — AGROTE43HNY. 809 



fairly rapidly through the system. Slight vacuum should be maiutained. The 

 essentials of the method are very slow aspiration at first, constant agitation, 

 and slight vacuum." 



If finely ground, limestone and dolomite can 1)0 examined for carbonic acid 

 by the method with or without soil, under the above condrtions. Dilute phos- 

 phoric acid In the cold is not ai)preciably active upon ferrous carbonate and but 

 slightly so on manganese carbonate. 



"In comparative carbon dioxid studies, a blank should be run ujion the soil 

 subsequent to its being freed of carbonates, and a correction made for the 

 action of the acid on organic matter." 



A bibliography is appended. 



Examination of artificial fertilizers (ZtscJtr. Landw. Vcrsuch.'iw. Oaten:, 

 15 (1912), No. 7, pp. 850^86) .—The methods included deal with the collection 

 and preparation of samples; examination of fertilizers containing (a) phos- 

 phoric acid, (b) potassium, (c) nitrogen, and (d) lime; general methods for 

 moisture; fine powder in Thomas slag powder; perchlornte in saltiieter; sul- 

 phocyanid in ammonium sulphate; lime and magnesia; sulphuric acid; iron and 

 aluminum oxids ; calcium sulphate; carbon dioxid; and the chloroform extract 

 of bone meal. In addition to limits of error and the methods of reporting 

 results are discussed. 



In the appendix the preparation of the reagents is described, and a table is 

 given for calculating phosphoric acid (P2O5) from magnesium pyrophosphate 

 and potassium from potassium perchlorate. 



Application of the microscope to the analysis of fertilizers, E. Collin 

 (Ann. Falsif., 6 (1913), Xn. 51, pp. l-'f-2-'f. figs. 0).— This deals with the histo- 

 logic features of the various organic substances which go to make up fertilizers. 

 Especially considered are dried blood, iwwdered meat, insect debris, horny ma- 

 terial, tannery waste (hides), waste hair, silk, wool, feathers, peat, and 

 charcoal. 



In regard to the determination of water-soluble phosphoric acid in super- 

 phosphates, F. PiLZ (Ztschr. Landw. Tcrsuchsio. Osterr., 15 (1912), No. 11, 

 pp. 1238-1244). — The method originally adopted by the Austrian Association of 

 Agricultural Experiment Stations consists of placing 20 gm. of superphosphate 

 (or 10 gm. of double superphosphate) in a Stohmann liter flask with about 

 800 cc. of distilled water and shaking In a rotary apparatus (30 or 40 revolu- 

 tions per minute) for one-half hour at room temperature. The mixture is then 

 made up to the mark, shaken thoroughly, and filtered through a dry folded 

 filter into a dry glass. By filling up the flask before rotation higher results 

 are obtained, and this change has been adopted by the association. 



Soluble silicic acid in Thomas slag- powder and its influence upon the 

 determination of citric acid-soluble phosphoric acid, M. Popp et al. (Landw. 

 Vers. Stat, 79-80 (1913), pp. 229-278).— A detailed account of material pre- 

 viously reported from other sources (E. S. R., 20, p. 410). 



The determination of citric acid-soluble phosphoric acid in Thomas slag 

 powder, W. Simmermacher (Chem. Ztg., 37 (1913), No. 15, pp. 145, I46; ahs. in 

 Chem. Abs., 7 (1913), No. 13, p. 2278).— A. review of methods and a discussion 

 of Popp's method (see above). 



The detection of alum in bread, J. R. N. Van Kregten (Chem. WeckbL, 

 10 (1913), No. 3, pp. 58-60; abs. in Chem. Ah'^., 7 (1913), No. 13, p. 2262).— In 

 addition to examining the ash. 2 reactions must be used. One of these is with 

 tincture of hematoxylin (logwood) ; the other, which utilizes alizarin, must be 

 modified for use with bread. Both reactions are given in the Codex Alimen- 

 tarius. 



