WATER SOILS. 1021 



cent. Of the totul amount of lime present in the soils ^-i.l per cent 

 was found in particles from 0.2 to 6 mm. in diametei-, 21.6 per cent in 

 the line sand, and 54.3 per cent in the dust (silt). In certain of the 

 soils, especially the heavy soils, a considera])le proportion of tiie lime 

 was apparently in the form of silicate. As regards the intluence of 

 the lime on the g-rowth of plants as determined in ]iot expei'iments, the 

 various lime compounds tested stood in the following order, begin- 

 ning with the highest: (1) Carbonate and caustic lime, dolomite^ and 

 basalt; (2) Thomas shig, scolecite, anorthite, dial)ase, and nephelinite; 

 (H) apophyllite; (4) phosphorite; (5) dicalciimi phosphate and apatite; 

 ((>) fluorspar, and (7) monocalcium phosphate. Gypsum gave negative 

 results. The highest yields were obtained ^vhen a mixtui-e of calcium 

 carbonate, mi^gjiesium carbonate, burnt lime, and burnt magnesia was 

 applied. Of the phosphates, Thomas slag gave the best results, dical- 

 cium and monocalcium phosphate the poorest. The poor results- 

 obtained with the superphosphate are attributed to the fact that it 

 failed to neutralize the acid condition of the soil. Of the silicates, the 

 zeolites gave specially good results. The results with gypsum are in 

 direct contradiction to those usuall}' obtained in practice. Even in 

 case of leguminous plants the gypsum was without l>eneticial eft'ect. 

 The amounts of lime dissolved by concentrated and dilute h3"drochloric 

 acid bore no relation to the yield of crop or to the amount of lime 

 assimilated. Neither did the carbon dioxid content furnish a reliable 

 index of the amount of lime taken up by the plant, since a low per- 

 centage of carbon dioxid did not always indicate a deficiency of availa- 

 l)lc lime. There was no appreciable difference in the lime content of 

 the grain of rye grown on limed and on unlimed soils. The percent- 

 age of lime in the straw was increased by liming only when there was 

 no increased yield. The active forms of lime in the soil are undoubt- 

 edly carbonate, sulphate, and easily decomposatile silicates. The pro- 

 portions of these which are most available for plant growth may be 

 determined by treatment with neutral solutions of ammonium chlorid 

 or aiumonium nitrate. Digestion for 3 hours with 10 per cent ammo- 

 nium chlorid solution at lOO'- C. on a water bath is considered a 

 satisfactory means of accomplishing this. This method has decided 

 advantages over the old method of digestion in 10 per cent hydro- 

 chloric acid, since the lime can be directly determined without separa- 

 tion of silica. Moreover, the results obtained show a closer agreement 

 with crop results and with the amount of lime taken up by plants. 

 A lime content of 0.25 per cent b}^ this method is considered normal. 

 Less than 0.2 per cent indicates a deficiency of lime in the soil. 



The distribution of alkali in the soil of the experiment farm, 

 E. E. Slosson (Wi/o/iihif/ St(/. Rj)t. 1900^ pp. I^). — Determinations of 

 the amount of alkali in the soil at depths of from 3 in. to 3 ft. on 



