New Milford, Clarksville, Granville, Conn., per Tenn., per N. C., per cent. cent. cent. Particles larger in diameter 8.55 0.32 0.23 than 3.0 millimeters Particles of diameter from 3.0 4.96 0.45 15.04 millimeters to 1.0 millimeter Particles of diameter from 1.0 4.43 0.96 33.43 millimeter to 0.5 millimeter Particles of diameter from 0.5 11.86 1.25 18.82 millimeter to 0.25 millimeter Particles of diameter from 0.25 60.54 61.58 23.59 millimeter to 0.01 millimeter Particles smaller in diameter 9.66 35.44 8.89 than 0.01 millimeter ─────────────────────────────────────────────────────────────────────── Total 100.00 100.00 100.00 =205. Method of Bennigsen.=—The silt flasks recommended by Bennigsen[139] are shown in Fig. 27. The glass flask _b_ carries a long cylindrical neck _a_ the upper part of which is graduated in cubic centimeters. Ten grams of the fine soil are shaken with water in the flask, the neck of which is closed with a rubber stopper. The flask is then inverted bringing the soil and water into the neck. The flask is hung up and sedimentation is assisted by imparting a pendulous motion to the neck for ten minutes. After an hour the soil particles have separated into a coarse layer below and a fine layer above. The relative volumes of the two layers are then read off in cubic centimeters. While this method may be useful in helping to form a speedy judgment concerning the character of a soil it can lay no claim to being an accurate method of silt separation. [Illustration: FIGURE 27. BENNIGSEN’S SILT FLASKS. ] =206. Method of Gasparin.=—The method of Gasparin only gives a very primitive separation of the various components of the earth according to their fineness. It is conducted as follows: Ten grams of sifted earth are put into a beaker, water is added and strongly agitated; after five minutes the water is decanted into another vessel, the first vessel is filled anew with water, agitated, decanted, and this process is repeated until the liquid remains perfectly clear. Only two portions are weighed, _i. e._, the pebbles which remain in the sieve and the coarse sand which remains in the beaker; while the argillaceous portion drawn off with the water is determined by the difference. =207. The Italian Method.=—The following modification of Gasparin’s process is practiced by the Italian chemists:[140]