.')4<> EXPERIMENT STATION RECORD. 



Those particles of the soil which passed through the sieve with holes 0.25 nun. in 

 diameter ami were collected in a porcelain dish are a Unwed to settle during 5 minutes 

 in a layer <if water 10 em. in height, as follows: The contents of the dish are trans- 

 ferred, in successive portions, to a beaker of 200 to 250 cm. capacity, which is 

 provided with a mark 10 cm. from the bottom. The beaker is each time filled to 

 tlie mark, the particles allowed to settle during 5 minutes, when the particles which 

 have not settled are decanted into a glass dish with vertical walls, of 3 to 3.5 liters 

 capacity (also provided with a mark 10 cm. from the bottom). The particles which 

 settle at the bottom of the beaker have a diameter o.l'.") to o.ol mm. < >n drying the 

 particles 0.25 to 0.05 mm. in diameter can he separated from those 0.05 to 0.01 mm. 

 in diameter by Schone's apparatus, so regulating the stream of water that its velocity 

 in the cylindrical part of the funnel-shaped vessel is equal to 2. 1 1 mm. a minute. 



The liquid with the suspended particles obtained by pouring off after 5 minutes 

 settling is allowed to stand in the jdass dish during 24 hours. The particles which 

 remain suspended | less than 0.001 mm. in diameter i are siphoned off into a tall glass 

 cylinder with a capacity of 8 liters. The residue in the dish is once more stirred up 

 with water added to the mark and again allowed to settle and the supernatant 

 liquid decanted. 



To insure a complete separation of the very line particles it is sometimes necessary 

 to boil the residue remaining in the glass dish with water for 12 hours, using for 

 this purpose an enameled iron dish. In that case the contents of the iron dish after 

 digestion are passed through a sieve with holes 0.25 mm. in diameter, in order to 

 break the aggregates which sometimes form in boiling, into a glass dish with a mark, 

 like the one mentioned above, but of less capacity. 



After standing 6 hours the coarsest particles settle at the bottom of the glass dish 

 while the liner particles, with an admixture of line silt, remain suspended. The sus- 

 pended particles are siphoned off into another dish and allowed to settle during 24 

 hours. The turbid liquid containing the fine silt is siphoned into the tall cylinder 

 which already contains the main bulk of the silt of the sample. The coarser parti- 

 cles in the 2 dishes are treated with successive portions of water until the liquid 

 above them, after settling, contains little suspended matter. The sediments thus 

 obtained are then transferred with the aid of small quantities of water into beakers, 

 1 to 2 ce. of a saturated solution of calcium chlorid are added, and when the solu- 

 tions above the residues have become clear the latter are filtered through weighed 

 filters. The washing to remove the calcium chlorid adhering to the residues is 

 continued until the filtrate begins to pass through turbid. The residues are then 

 dried at 100. to 110° and weighed. 



Finally the liquid in the tall cylinder containing the silt is treated as follows: After 

 a considerable quantity of the liquid has been transferred from the dishes into the 

 cylinder 20 to 25 cc. of a saturated solution of calcium chlorid are added, the liquid 

 is stirred up and allowed to -stand for some days until the silt settles at the bottom 

 and the supernatant liquid becomes clear. The clear solution is siphoned off and 

 fresh portions of the liquid, from the dishes, containing silt are transferred to the tall 

 cylinder and treated in the same way. The silt, upon removal of the clear solution, 

 is, as was the case with the coarser particles, washed with the aid of a little water into 

 a beaker, treated with 1 to 2 cc. calcium chlorid, filtered through a weighed filter, 

 dried, and weighed. 



In obtaining the mechanical constituents of the soil for his experiments the author 

 had to avoid the operation of boiling since he found that plants develop better on 

 soils which were subjected to boiling fort) hours than on the same soils not so treated. 

 In order to disintegrate the small lumps he poured the particles of the soils which 

 passed a sieve with holes 3 mm. in diameter into a Schone apparatus filled with 300 

 cc. of water and agitated them by sucking air through the apparatus. Passing the 



