A NOTE ON THE CLASSIFICATION OF SOILS 

 ON THE BASLS OF MECHANICAL ANALYSES. 



15 Y C. L. WHITTLES, 



School of Agricullure, Cambridge. 



(With Eleven Figures.) 



Although many schemes have been proposed for a classification of soils', 

 not any single one seems to have found general acceptance. It is, how- 

 ever, generally agreed that with any method, a final subdivision based 

 on the texture of the soil is highly de.sirable, even though it only be the 

 sands, loams, and clays of common jjarlance. (Jranted then that a 

 classification based on mechanical analyses is called for — though not 

 necessarily as the j)riiiiary division into groups — it is here proposed to 

 examine some of tJie various methods so far put forward for dealing with 

 the results of mechanical analyses. Tables of analytical results in them- 

 selves are unwieldy and make decidedly iminteresting reading. The com- 

 parison of a large number of soils is a slow and tedious proce.-^s, if it is 

 accomphshed only by a study of the figures. 



Hope and Carpenter(22) have devised a method by whicii one can 

 rapidly refer a soil to one of twelve types. In their classification the 

 particles are classified into four groups, the limiting dimensions of which 

 are given in Table I. 



Table I. Hope and Carpenter's Classification of Parlides. 



Limiting diameter in mm. 



Four broad divisions are distinguished according as one or other of 

 these fractions occurs in the largest percentage. Each of these divisions 

 is subdivided into three classes according as one or other of the three 

 remaining fractions pre])onderates. Each ingredient is represented by 

 a number (1, 2, 3 or 1), and the type is named by placing the division 



• See Bibliography. 



