82 THE PHYSICAL PROPERTIES OF SOILS 



Sterilizing bottle (T), add about 150 cc. of distilled 

 water and ten drops of ammonium hydrate to break 

 up flocculation. Place the bottle in the mechan- 

 ical shaker and agitate until, when viewed under the 

 microscope, the soil particles are free from each other 

 and present a clear-cut appearance. 



Transfer from the shaker-bottle to the apparatus 

 shown on page 80 (T). Adjust this bottle so that 

 the opening into the long tube will be i^ inches from 

 the bottom. Fill to the 3-inch mark by means of a 

 small jet of sufficient force to thoroughly stir up the 

 contents. 



Allow the apparatus to stand until a microscopic 

 examination shows that all of the sand grades have 

 settled below the opening of the tube. Blow off into 

 a beaker all of the liquid above the end of the tube, 

 and continue the operation of filling, settling and 

 blowing off until the grades that settle contain no silt 

 or clay. The liquid blown off contains the silt and 

 clay, the amount of which is determined by evaporating 

 to dryness and weighing. No attempt is made at this 

 time to separate the silt from the clay. 



The decanting process may be continued for the sep- 

 aration of the finest sand grades, or the material may 

 be dried and the separation made by means of a nest 

 of sieves. After the removal of the sands the bottle 

 is used to accomplish the separation of the clay from 

 the silt. 



Tabulate the results of the analyses. 



Reference : 



Bulletin No. 24, Bureau of Soils. 



