54 THE MECHANICAL ANALYSIS OF SOILS [chap. 



and scraped out into a bag for conveyance to the labora- 

 tory ; two or three samples to the same depth being 

 taken from the same field and afterwards mixed. 

 Should samples of the subsoil be required, the box 

 is left in position after its contents have been scraped 

 out, and the surrounding soil is dug away to the 9-inch 

 level, the box is then rammed down for the second 

 9 inches, and its contents removed : the process being 

 repeated till the required depth has been reached. 



A modification of the Rothamsted method consists in 

 marking out on the surface a square 9 inches on the 

 side, and digging away the surrounding soil until a 

 9-inch cube of earth remains standing ; over this a 

 wooden box is slipped, and the cube is cut off by pushing 

 a spade beneath at the 9-inch level. 



On soils which do not contain many large stones, 

 samples may be taken with an auger, both more rapidly 

 and with greater security of obtaining an average 

 sample. A convenient tool for the purpose consists of a 

 cylindrical auger made of steel, about yV inch thick, of 2 

 inches internal diameter and 12 inches deep, with a slot 

 f inch wide running from top to bottom ; the lower 

 edge of the cylinder and the edges of the slot are 

 sharpened ; to the upper end of the cylinder a handle 

 carrying a wooden crossbar is riveted. The auger is 

 forced gently into the soil with a twisting motion until 

 the required depth is reached, when the tool is with- 

 drawn and the core scraped out into a bag. Six to ten 

 cores at least are taken at regular intervals in the same 

 field and mixed to secure an average sample. Each 

 boring can be continued to obtain subsoil samples as 

 deep as the length of the handle permits. It is impos- 

 sible to obtain samples with the auger when the soil is 

 dry. Fig. 2 shows a photograph of both types of soil- 

 sampling tools. 



