90 SOILS AND MANUKES 



and gases respectively in two cultivated soils examined by 

 the author were as follows : 



i. ii. 



Space Occupied. Space Occupied. 



Per cent. Per cent. 



Solids 32-3 39'7 



Water . . . . 37'3 \ 47-1 ] 6Q . 3 



Gases .... 30'4 J 18*2 J 



100-0 100-0 



In sample I. the water amounted to 55 per cent, of the 

 total capacity of the soil (i.e., total interspace), and plenty 

 of space was left for air. The physical properties of the 

 soil were therefore, to this extent, excellent. 



Sample II. was a soil which had been for a long time 

 under grass, and, though formerly fertile, had in recent 

 years yielded very poor crops. Heavy dressings of farm- 

 yard manure and various kinds and combinations of arti- 

 ficial manure produced little or no effect, and chemical 

 analysis showed that it was not deficient in plant foods. 

 The explanation is to be found in the figures given above. 

 Though not badly drained, the water amounted to over 78 

 per cent, of the total capacity of the soil, and the air space 

 was reduced to 13*2 per cent, of the total volume. This 

 soil was a stiff clay, in which the colloidal matter had 

 become defloculated and blocked up the pores. Super- 

 ficially it presented the appearance of a homogeneous 

 jelly. It is almost superfluous to add that the proportion 

 of lime in this soil was exceedingly small. 



The retentive power for water can best be judged from 

 the amount found in the soil, as above described, if 

 the sample is taken soon after the discharge of drainage, 

 following upon heavy rain, has ceased. Eesults obtained 

 by saturating a sample of soil with water in the laboratory 

 and estimating the quantity left in it after draining are 



