94 



SOILS AND MANUEES 



after standing for a farther and longer period is decanted 

 off and added to the third sediment. This process 

 must be repeated and repeated again until the size 

 of the particles in each group is fairly homogeneous. 

 The particles in each group are then collected, weighed, 



FIG. 15. 



and their size determined by microscopic measurement. 

 The process is easily carried out, but, when many groups 

 are required, it is long and tedious. 



When particles of all sizes are uniformly distributed 

 through a liquid, the larger particles settle faster than the 

 smaller ones, but some of the smaller particles near the 



