MECHANICAL ANALYSIS OF SOIL. 



x 



from the second through the third. Wash 

 the residues in each of the sieves, with gentle 

 stirring, until the water coming away ceases 

 to be muddy. Put aside the sieves, with their 

 contents, to dry. Collect the washing waters 

 together and stir well. After standing two or 

 three minutes pour away the muddy water 

 from the sandy sediment, wash the sand into 

 a tumbler and again wash with gentle stirring 

 and rubbing with the wooden or rubber-tipped 

 rod. After standing a short time once more pour 

 the water from the sandy sediment. Repeat 

 this process until the water ceases to become 

 turbid. 



3. Dry the various portions separately and 

 weigh them ; the different grades may be desig- 

 nated as follows : From the first sieve, coarse 

 gravel ; from the second sieve, gravel ; from the 

 third sieve, coarse sand ; the residue from wash- 

 ing, sand. The amount carried away in the 

 water may be found by adding together the 

 weights of the various grades obtained and de- 

 ducting this from the total weight taken to be 

 operated on. The difference may be called 

 silt and clay. The quantities should be calcu- 

 lated in percentages. Samples of the separated 

 grades should be put into tubes or small bottles 

 and kept as a record and for future reference. 



