1918] AGEICULTUKAL CHEMISTRY AGROTECHNY. ' 313 



of ammonium sulphate and ammonium cliloi'id to insure an excess of appi'oxi- 

 mately 0.3 gm. of sulptiate is added. The materials are thoroughly mixed in 

 the crucible by means of a small glass rod. The crucible is now inserted in a 

 circular opening cut in a piece of asbestos board placed horizontally, the upper 

 half of the crucible extending above the upper surface of the asbestos. A nearly 

 horizontal flame from a small Bunsen burner is directed across the surface 

 of the crucible in such a manner as to have the side of the crucible nearest 

 the flame intensely heated. The conducted heat will effect volatilization without 

 spattering. 



The procedure has been thoroughly tested and found to be reliable and espe- 

 cially well adapted for determining large amounts of lime and also In sets 

 containing widely varying percentages. 



A modified method for the determination of fluorin with special application 

 to the analysis of phosphates, C. R. Wagner and W. H. Ross (Jow. Indus, 

 mid Engin. Chcm., 9 {IQIT), No. 12, pp. 1116-1123, fig. i).— The authors have 

 studied the various methods which have been proposed for the determination 

 of fluorin in the presence of phosphorus, and have developed a procedure which 

 consists in volatilizing the fluorin as silicon fluorid, collecting the latter in 

 water to form hydrofluosilicic acid, and titrating the acid with standard sodium 

 hydroxid, using phenolphthalein as indicator. The apparatus necessary in the 

 procedure and its manipulation are described in detail. In samples previously 

 freed from water and organic matter (by burning) a complete analysis can 

 be effected in one hour. The method is indicated as being applicable to material 

 containing as low as 0.01 per cent fluorin. 



The sulphur trioxid, sulphur dioxid, and other products evolved, which may 

 be present as hydrochloric and nitric acids, are removed by selective reagents 

 through absorption so that a hydrofluosilicic acid entirely free from other acid 

 constituents is obtained. 



The mechanical analysis of soil, U. Pratolongo {Staz. Sper. Agr. Ital., 50 

 {1917), No. 3-5, pp. 111-166, figs. ^).— The material reported is divided into three 

 parts, (1) the problem and methods of the mechanical analysis of soil, (2) a 

 new rapid method for the mechanical analysis of soil, and (3) experimental 

 researches on a method of mechanical analysis by sedimentation. 



The apparatus and the manipulation of the new method are described in 

 detail and the experimental data reported in part S are discu.ssed.. 



A note on a modified method for determining carbonates in soil, H. A. 

 Tempany and R. E. Kelsick {West Indian Bui., 16 {1917), No. 3, pp. 259-261, 

 fig. 1). — A modification of the method previously described by Watts (E. S. R., 

 14, p. 848), which consists essentially in the substitution of an ordinary water 

 filter pump for the mercury pump originally employed and in the use of an 

 ordinary suction flask in place of a special receiver for the absorption of cai-bon 

 dioxid by the barium hydroxid. is described. Comparative determinations with 

 the original method show the modified procedure tc yield accurate results and 

 to possess a number of advantages. 



Examination of water, W. P. Mason {New York: John Wiley d Sons, Inc., 

 1917, 5. ed., rev., pp. VI -{-186, pis. 2, figs. i9).— This is the fifth edition of the 

 well-known work previously noted (E. S. R., 23, p. 11). 



A volumetric method for the determination of formic acid or formates in 

 the presence of hydroxids, carbonates, oxalates, and acetates, F. Tsieopinas 

 {Jour. Indus, and Engin. Chetn., 9 {1917), No. 12, pp. 1110, 1111, fig. 1).—K 

 method, which is based on the quantitative oxidation of formic acid to carbon 

 dioxid by chromic acid in boiling solution, and the necessary apparatus and its 

 manipulation are described in detail. The carbon dioxid evolved is measured 



