170 



97. ANALYSIS OF SOILS AND EOCKS. 



meshes 1 mm. wide, is stirred up with water ; in case 

 there is reason to suppose that funnel No. 2 will not hold 

 all this mixture of soil and water, a part of the latter, 

 holding only the finest particles in suspension, may be put 

 in funnel No. 3 ; then pour the rest of the mixture, just 

 after it has been well stirred, into the second funnel, 



Fig. 6. 



while any very coarse sand remaining in the beaker may 

 be rinsed into the first funnel ; but it is better to put the 

 whole in the second funnel, if possible. 



All the funnels are then filled with water, the connec- 

 tions carefully made between them with gum tubing, and 

 the siphon leading from the reservoir is filled and con- 

 nected with the smallest funnel. As soon as 9 litres of 

 water have passed through, the connection with the 

 reservoir is closed by means of a clamp on the gum tube. 



The whole apparatus is then allowed to stand about 

 five hours, until the solid matters in the funnels have 



