WATER SOILS. 433 



would have some effect in retaining moisture per se, and independent of any modifi- 

 cation of the arrangement or of the size of the .soil particles or of the surface tension 

 of the soil water. The results, however, show no changes which are proportional 

 to the hygroscopicity of the salts used. In the untreated soil the capillary rise 

 reached its limit at 50 in. in 110 days, in the soil plus gypsum 51 in. in (58 days, the 

 soil pins calcium carbonate 50 in. in 72 days, soil plus calcium superphosphates 51 in. 

 in 105 days, soil plus magnesium oxid 47 in. in 80 days, and soil plus magnesium 

 carbonate 47 in. in 70 days. The soil column containing potassium sulphate was still 

 rising when it reached the end of the tube at 60 in. in 110 days. This is an increase 

 of 5 in. in height over that in the untreated soil. It is most probable that those sails, 

 such as potassium chlorid and potassium nitrate, which reduced the rate of rise more 

 than potassium nitrate, would also have increased the height of lift more than did 

 tin' potassium sulphate. It seems to be a general rule, then, that those salts which, 

 when added to a soil, reduce the rate of rise of capillary moisture increase the height 

 of lift; and conversely that those salts which increase the rate of rise decrease the 

 height of lift. These variations in rate and height of capillary lift and in rate of 

 evaporation do not correspond to the changes in the surface tension of water caused 

 by these salts, as was found to be true in the study of the rate of saturation and 

 percolation." 



The author considers it desirable, in order to save time, to develop 

 an empirical formula for calculating the height of lift, and states his 

 intention to attempt to work out such a formula. 



The results of the above experiments show in general that most of 

 the salts in the amounts usually applied in agricultural practice would 

 have little effect upon the soil supply of moisture. Carbonate, chlorid, 

 and nitrate of soda, however, may be utilized with decided effect as a 

 means of increasing the soil's capacity for storing up and retaining 

 moisture. 



It is believed that by means of the method of studying the physical 

 properties of soils here described positive information concerning the 

 moisture needs of a soil and the kind of crop best adapted to it maybe 

 obtained without the necessity of waiting a year for the results of field 

 experimentation. It is suggested that the stations might profitably 

 study the subject of fertilizing soils with reference not only to their 

 needs of plant food, but also to their moisture requirements. 



Water purification, T. B. Carpenter (Albany Med. Ann., 1897, Xo. 3-4, pp. 141-161). 



Methods for preventing the pollution of -water, E. K. Dunham (Albany Med. 

 Ann., 1807, No. 3-4, pp. 16:2-167). 



Common causes of the contamination of drinking water, T. M. Cheeseman 

 (Albany Med. Ann., 1897, Xo. 3-4, j>p. 115-121). 



On the movement of water in the soil, D. Kitao (College Ayr. Tokyo, Bid., vol. 

 3, No. 1, p. 113). — The mathematical features especially of this subject are elaborately 

 worked out. 



On the surface temperature of the soil, H. de Varigny (Jour. Soc. Agr. Brabant- 

 Hainaut, 1S97, Xo. 24). 



On the dialysis of alkaline humates, J. Dumont (Jour. Soe. Agr. Brabant-Hainaut, 

 1897, Xo. 22). 



Investigations on the changes in volume of different kinds of soil, E. Wollny 

 (Forsch. deb. agr. Bhys., 20 (1897), Xo. 1, pp. 1-52, fig. 1).— This article discusses at 

 length the results of experiments on the influence of tillage and wetting and drying 

 on the volume of soils of different chemical and physical character. 



