Two cylinders are placed vertically, one over the other. The lower cylinder is graduated in cubic centimeters, the upper cylinder is closed at each end by perforated rubber stoppers A and B through the openings of which the glass tubes _c_ and _d_ pass. Within the cylinder A the opening of the small tube _d_ is closed with a disk of Swedish filter paper. The lower part of the small tube is _d_ connected by means of a rubber tube carrying a pinch-cock C, with another small tube _e_ which passes through the stopper _f_. In carrying out the process the weighed quantity of soil is placed in the upper cylinder and afterwards the measured quantity of the solution, the whole thoroughly mixed and the cylinder closed. The valve C is then opened, a given quantity of the solution, but not all, is made to drop into the lower cylinder and the valve C is then closed. The liquid which has passed into the lower cylinder as well as that which remains in the upper cylinder, is thoroughly stirred and the quantity of the material remaining in both liquids determined and the absorbing power of the soil estimated from their difference. It does not appear that this method of estimation of the absorption power possesses any special advantages over the old and far simpler method of shaking in a flask. [Illustration: FIGURE 16. MÜLLER’S APPARATUS TO SHOW ABSORPTION OF SALTS BY SOILS. ] =134. Method of Müller.=—The method of Müller[97] for illustrating absorption is carried out by means of the apparatus shown in Fig. 16. A glass cylinder A about 750 centimeters long and four to five centimeters wide is closed at each end with rubber stoppers with a single perforation. The cylinder A is for the reception of the soil with which the experiment is to be made. Before using, the lower part of it is filled with glass pearls or broken glass and above this a layer of glass wool is placed about one centimeter thick. The object of this is to prevent the soil from passing into the small tube below. As soon as the soil has all been placed in the cylinder A the upper part of the tube is also filled with glass wool. The cylinder A is connected with the pressure bottle B by means of a rubber tube and the small glass bulb tube shown in the figure. The bottle B should have a content of about two liters. It is filled with the standard solution of the material of which the absorption coefficient is to be determined. At _c_ the rubber tube is connected with a glass T one arm of which is provided with a piece of rubber tubing which can be closed by means of a pinch-cock. At _c_ a screw pinch-cock is placed which can be used to regulate the flow of the solution from B to A. By opening the pinch-cock at _e_ on the short arm of the T piece, a sample of the original liquid can be taken and this can be compared with the part which runs to _b_. If it is desired for instance, to show that potassium carbonate has been absorbed