=219. Schöne’s Method as Practiced by Osborne.=—The apparatus used by Osborne[151] was obtained from Germany and was similar to that described by Schöne in his original paper, except that it was furnished with a second elutriating tube as suggested by Orth. The modification made by Orth consists, essentially, of a second elutriating tube with straight sides into which the bulk of the soil is introduced, only the final part being carried over into the Schöne’s tube proper. Water is supplied to the apparatus under constant pressure by means of a Mariotte’s bottle. The preliminary treatment recommended by Schöne is omitted, as these steps have been shown to be undesirable, on account of affecting the accuracy of the results. Twenty grams of the air-dried soil are passed, under water, through a sieve of one-fourth millimeter mesh. That part of the soil which remains in suspension after being sifted is placed at once in the Schöne’s tube of the apparatus, the coarser portion being rinsed into the Orth tube. The current is regulated so that the largest particles of quartz carried off have an average diameter of 0.01 millimeter. When all is carried off that can be removed at this rate the current is increased until the largest quartz grains passing off have a diameter of 0.05 millimeter. As noticed by Hilgard with Schulze’s apparatus, secondary currents are formed during the process of elutriation which descend along the walls of the conical portion of the Schöne’s tube and some distance along the sides of the cylindrical portion. The tendency of these currents is to produce globular aggregates of particles which fall to the bottom. They are broken up from time to time by increasing the velocity of the current but even this method fails to disintegrate a considerable quantity of them. =220. Statement Of Results.=—Two samples of soil from the garden of the experiment station analyzed by Schöne’s method gave the following proportions of sediment. In the table the term clay is used to designate all that part of the soil which has diameters less than 0.01 millimeter and which remains suspended after twenty-four hours standing in water having a depth of 200 millimeters. SOIL, FROM GARDEN OF THE EXPERIMENT STATION.—NOT BOILED. Analyses with the Schöne-Orth Elutriator. _A._ _B._ _C._ Above 0.25 millimeter 48.82 48.82 48.82 0.25–0.05 27.36 29.94 22.37 0.05–0.01 millimeter 8.63 6.07 13.70 0.01 millimeter and less depos. 7.36 7.31 7.20 Clay (by difference) 1.00 1.03 1.08 Loss on ignition 6.83 6.83 6.83 —————— —————— —————— 100.00 100.00 100.00