Sol aide Constituent.<i in Alluvial Soil. 39 



layers, and will actually do so if no causes are at work in the 

 opposite direction. When evaporation is going on the reverse 

 takes place, the dilute solutions drawn up by capillarity con- 

 centrating at the surface. The purpose of the following re- 

 search has been to determine how pronounced these movements 

 are during an ordinary season, whether they are shown when 

 the land is growing a crop, how manuring affects them, and 

 whether any changes are also shown in the percentage of acid- 

 soluble constituents, and of humus at different depths through- 

 out the year. For this jiurpose, Mr. Luffmann was so good as 

 to allow Mr. A. G. Campbell to start a series of experimental 

 plots at the Burnley Gardens. These were selected and made 

 up so as to be as uniform as possible throughout each of the 

 two sets of series, one being composed of a fine ' alluvial sandy 

 soil, the other a rather fine clay, and both halving a subsoil 

 nearly sixteen inches below the surfajce, as will be seen by refer- 

 ence to the following report by Mr. Campbell : — 



The soils selected were : — (I) A leached basalt clay, shallow, 

 overlying a very tough clay subsoil ; and (II.) deep sand of al- 

 luvial nature, overlying white sandy subsoil, with some clay. 

 By preparing the beds well, the subsoil in the first instance 

 was put abiiut 12 inches below the surface, and in the second 

 15 inches. The elevated beds remained high and dry all the 

 winter, even in series I., which was on quite fiat land. The 

 sandy lot sloped very slightly southward. The plots in each 

 series were each 1 square pole in ai'ea (30^ square yards), and 

 treated as follows, the quantities per acre being given in the table 

 of results. The manures were applied in quantities much above 

 ordinary agricultural practice, although the land wais already in 

 good heart, since otherwise the amounts in the soil would be 

 almost imperceptible. 



PI. 



