64 



THE TEXTURE OF THE SOIL 



[chap. 



made in the laboratory, of the apparent density of 

 various soils in a roughly powdered state and without 

 the stones, which, being solid, would add to the apparent 

 density of the soil. The results are also recalculated 

 to show the weight of a cubic foot of the soil, and the 

 weight per acre of a layer 9 inches deep : — 



The figures given above are not exactly comparable 

 with soils under natural conditions, because of the 

 powdering, the exclusion of stones, etc., but they 

 serve to show that the clay soils usually described as 

 "heavy" are really less dense, and weigh less per cubic 

 foot than some of the lighter soils, whereas pure sands 

 are the densest of all. The farmer's terms of " light " 

 and " heavy " land refer to the draught of the plough, 

 the resistance the soil opposes to being torn asunder, 

 and not to the actual weight of the portion moved ; 

 sands which he calls " light," being, as the table shows, 

 heavier per cubic foot than the clays which the farmer 

 calls heavy soils. 



This point will be further elucidated by the following 

 table, which shows the weight per cubic foot of the 

 arable soils at Rothamsted and Woburn down to a 

 depth of 3 feet These results represent the real weights 

 of the soil as obtained by cutting out a block 6 inches 

 square by 9 inches deep, weighing it, and afterwards 



