WATER SOILS. 229 



at the central lal)<>rat(>rv at (iuati-iuala ami l>y (•(>oin'ratin','(>l).st'rv('rs in iliffcivnt parts 

 of the repnl)M<'. 



Formation of hail and surfusion, Kosenstiehl ( Orele, 2 {1901), Xo. 6, pp. .i-s). — 

 A (liscus-^ion of the tlieories of the formation of hail. 



Cannonading against hail in Belgium, J. Vaxdervaekex {Rev. Gm. Ayron. 

 [Lourahi], 10 {1901), Xos. 4, pp. 145-163, figs. 8; 5, pp. 201-216, pi. i).— The extent 

 and resnlts of this method of protection against hail in Belgium are reported, the con- 

 clnsion being that it lias 1 )een decidedly profitable in protecting glass houses and crops. 



Protection against hail, J. Roberto {GnUe, 2 {1901), Xos. 6, pp. 9-15; 7, pp. 11- 

 16,fi(js.2; 8, pp. 6-10). 



An easily constructed barometer, G. W. Russell {Amer. Chem. Jour., 25 

 {1901), Xo. 6, pp. 508-510, fig. 1). 



WATER— SOILS. 



Development and distribution of nitrates and other soluble salts in culti- 

 vated soils, F. II. KiX(; and A. R. Whitsox ( Wlscunsin Sfo. Bid. 85, pip. 48, figs. If) . — 

 This is in large part a reprint, with more detailed data, of an account of investiga- 

 tions already noted from another publication of the station (E. S. R., 13, p. 24), but 

 contains also accounts not previously reported of investigations on the limit of nitric 

 nitrogen in field soil at which the leaves of corn and oats turn yellow, difference 

 between the amounts of nitric nitrogen under growing crops and in cultivated fallow 

 ground at the same time, distri])utiou of nitrates and other soluble salts in scjil under 

 growing corn as it comes into full tassel, the strength of soil solutions under lield 

 crops, results of Warington's nitric nitrogen studies at Rothanisted, method of deter- 

 mining solu])le salts and nitric nitrogen in field soils, sensitiveness of the methods 

 used in the study of nitric nitrogen and solul)le salts, and possible error in results 

 due to the methods. 



The investigations reported in this bulletin were made on 9 plats of soil aggregat- 

 ing 10 acres, and covered the first, second, third, and fourth feet of soil separately 

 in each case. The objects were to study the variations in the amount of nitric nitro- 

 gen and S(jluble salts in the soil under different conditions of cropping and culture, 

 to determine the amounts of nitric nitrogen in the soil required for the healthy 

 growth of crops, to trace the relations, if any, between the amount of nitric nitrogen 

 and total soluble salts in the soil water and that of the deeper ground water wells, 

 and to devise an accurate, rapid, and sensitive method for the determination of 

 nitric nitrogen in soils. The conclusions drawn from the work are as follows: 



"(1) The nitrates and total soluble salts in the surface foot start in the spring (com- 

 paratively small in amount, then increase somewhat rapidly until June 1 on clover 

 and oat grovmd, and until July 1 on corn and ijotato ground; from these dates they 

 fall more or less rapidly until August 1, when crops are growing most vigorously. 

 After this date they remain nearly constant with a general tendency to rise slightly 

 until September. In the third and fourth feet the seasonal changes are ccjmpara- 

 tively small and show but little progression, and they are not marked in tlu> second 

 foot. 



"(2) The amounts of nitrates and of soluble salts in the soil under the clover and 

 oat crops were much smaller than in the soil under corn and potato crops through 

 the entire season, the greatest differences occurring during the month of June. 



"(3) There has been no strong concordance between the yields of dry matter per 

 acre and the amounts of nitrates fomid in the soils during the season, but where the 

 yields have Ijeen relatively quite small, there too has been found amarkeil deficiency 

 of both nitrates and total soluble salts. In the case of the 8 corn crops the largest yields 

 of dry matter are associated with the largest total solul)le salts. 



"(4) The relation between the amount of nitrates in a soil and the total soluble 

 salts varies between wide limits, when the salts are measured by the electrical 

 method. It occasionally happens that there may be as much or even more nitrates 



