soils. 347 



current of air during 4 hours was sufficient for complete disintegration of the various 

 soils with which tin* author experimented. After the agitation by the current the 

 liquid, together with the sediment, was brought into a sieve with holes 0.25 nun. 

 in diameter, where the sandy part of the soil was separated. The further treatment 

 nl the soil was according to the Williams method. 



In the author's experiments oats were raised in 5 kg. pots filled with a mixture 

 of sterile sand and soil particles of different sizes prepared by the method described. 

 In the first series the mixture consisted of the sand and so much of the mechanical 

 element (silt, fine dust, medium dust, large dust, together with the sandy dust i as 

 was obtained from 2 kg. of the soil. In the second series of experiments the neces- 

 sary quantity of sand was mixed with normal soil and with the same deprived of one 

 or more of the mechanical grades of particles. In both series of experiments the 

 soils used were a clayey chernozem and a peaty clay. The third series of experi- 

 ments was carried out with equal quantities of the different mechanical elements 

 (each vessel receiving 250 gm. of the element in question and 4,500 gm. of sand). 

 Parallel experiments in the case of each element were carried out with nitrogen and 

 potash and with nitrogen and phosphoric acid. 



In this series of experiments as well as in the following series the mechanical ele- 

 ments of the upper layer of a podzol soil and of the parent rock under it were inves- 

 tigated. The phosphoric acid and the potash in the silt and coarser particles, anil 

 the nitrogen, phosphoric acid, and potash in the crops of oats obtained were deter- 

 mined. In the fourth series of experiments sand and such amounts of the corre- 

 sponding element were used that in the pots fertilized with nitrogen and potash the 

 phosphoric acid amounted to 0.25 gm., and in the pots fertilized with nitrogen 

 and phosphoric acid the potash content also amounted to 0.25 gm. 



The following are some of the conclusi< »ns drawn: ( 1 ) The total contents of potash, 

 phosphoric acid, and nitrogen in the mechanical elements of the soils investigated 

 decreases with the increase of their size; (2) assimilable substances for the plants are 

 contained not only in the silt, but also in the coarser grades; (3) since the very fine 

 particles are present in the majority of soils in small quantities the fertility of soils 

 depends largely upon the coarser particles; (4) the mechanical elements even of soils 

 of a like geological origin are unlike in their chemical composition and in the avail- 

 ability of their plant food ; hence it is impossible to judge of the fertility of a soil from 

 its mechanical composition. — p. fireman. 



The mechanical analysis of soils and the composition of the fractions 

 resulting therefrom, A. D. Hall (Jour. Chem. Soc. [Loudon], 85 (1904), No. 501, 

 pp. 950-96.3). — The author investigated the effect on the mechanical analysis of soils 

 of the preliminary treatment with dilute acid followed by ammonia, proposed by 

 Schloesing. 



For the separation into fractions, Osborne's method of sedimentation was adopted, 

 the soil being separated into two fractions by sieving and into five by sedimentation. 

 He found that the raw soil rarely yielded as much of the finest fraction, for which 

 the name "klay " is proposed, as was given by the same soil after washing with acid, 

 the difference being greatest with soils rich in humus, the reason probably being that 

 the humates, which act as a weak binding material, are decomposed by this treat- 

 ment. Soluble salts, which might interfere, are also removed. 



The difference shown by the two methods, however, practically disappears when the 

 soil has long remained unmanured or has been deflocculated by the continued use of 

 saline fertilizers. The Schloesing method consequently reveals the original character 

 of the soil, irrespective of its manuring. 



Investigations on the absorbent power of cultivated soils, C. Dusserre and 

 T. BrELER (Ann. Agr. Suisse, 5 (1904), No. 3, pp. 110-119, figs. 6).— The history of 

 the study of this property of soils from the time of its discovery by J. Gazzeri in 



