The author of the method claims that in respect of likeness of particles the results are especially gratifying and that duplicate analyses give results fully comparable. The process, however, has not commended itself to analysts, but it marks a distinct progress toward the principles of later investigators. Had each of the elutriating vessels been placed upright and the rate of flow determined, the apparatus of Dietrich would have served, to a certain extent, for the more rigid investigations of his successors. =216. Method of Masure.=—The sifted earth, from ten to fifteen grams, is carefully mixed with 200 cubic centimeters of water. It is then introduced into a doubly conical elutriator B, Fig. 30, of about 250 cubic centimeters capacity. A current of distilled water is allowed to flow from a Mariotte’s bottle, A, which secures a regular and constant flow. The bottle A is joined to the elutriator B by means of a rubber tube and the vertical glass tube D, the top of which is expanded into a funnel for the purpose of receiving the water from the Mariotte flask. The current of water flowing upward through the elutriator B carries in suspension the most finely divided particles of clay, and these are collected with the emergent water in the receiver C. The sand and coarser particles of clay remain in the elutriator. The water flows out by the tube F, the diameter of which should be less than that of D. When the emergent water becomes limpid the operation is terminated. After the apparatus is disconnected, the water is decanted from the sand in the elutriator, and the whole residue is weighed after drying for two hours at 110°. [Illustration: FIGURE 30. MASURE’S SILT APPARATUS. ] The fine soil collected in C may also be separated and weighed, for control, after drying as above. The pebbles and coarse sand separated by the sieves should also be weighed. By this process the soil is separated into four portions; _viz._, (1) Pebbles. (2) Coarse sand. (3) Fine sand and other materials not carried off by the current of water. (4) Fine soil, carried into the receiver C. =217. Method of Schöne.=—The method of Schöne[149] is based on the combination of a cylindrical and conical separatory tube through which the flow of water is regulated by a piezometer. If, in the process of silt separation, the water move perpendicularly upward with a given velocity, _e.g._ = v the separation is dependent: (1) On the volume of the silt particles, (2) On their specific gravity, and, (3) On their state of disintegration. If it be assumed that the silt particle is a sphere with a diameter = d, then according to Newton’s law of gravity, the following formula would be applied: d = v² ((3Z)/(4g (S − 1))). [Illustration: FIGURE 31. SCHÖNE’S ELUTRIATOR. ]