The bottom inclines from the sides towards the middle, and from the back to the front, thus forming a gutter which permits of the easy collection of the drainage. The drainage water is conveyed, by means of a pipe and a funnel, into a demijohn placed in the ditch in front of the apparatus, as shown in the figure. These receptacles stand in niches under the front of the cases, and are separated by the brick foundations. Access to them is gained by means of the inclined plane shown in the figure, and this plane permits the demijohns in which the drainage water is collected, to be removed with a wheelbarrow for the purpose of weighing. This apparatus is especially suitable for a study of the distribution of the nitrogen to the crop, the soil and the drainage waters. The loss in drainage waters of potash and phosphoric acid is insignificant in comparison with the loss in nitrogen. The cases having been placed in position they are filled with the natural soil, which is taken to the depth of one meter, in such a way that the relative positions of the soil and subsoil are not changed. While the soil is transferring to the cases it is carefully sampled in order to have a portion representing accurately the composition of both the soil and subsoil. These samples are subjected to analysis and the quantities of nitrogen, phosphoric acid, and potash contained therein carefully noted. One or two cases should be left without crop or fertilizer to determine the relations of the soil and subsoil to the rain-fall. Three or four cases should be kept free of vegetation and receive treatment with different fertilizer, in order to determine the influences of these on the deportment of the soil to rain-fall. The rest of the cases should be seeded with plants representing the predominant field culture of the locality, and some of them should be fertilized with the usual manures used in farm culture. [Illustration: FIGURE 24. DEHERAIN’S APPARATUS FOR COLLECTING DRAINAGE WATER. ] AUTHORITIES CITED IN PART THIRD. Footnote 70: Comptes rendus, Tome 112, p. 598. Footnote 71: Stockbridge, Rocks and Soils, p. 153. Footnote 72: Die Landwirtschaftlichen Versuchs-Stationen, Band 8, S. 40. Footnote 73: König, Untersuchung Landwirtschaftlich und Gewerblich Wichtiger Stoffe, S. 48. Footnote 74: Methods of Swedish Agricultural Chemists, translated for author by F. W. Woll. Footnote 75: Poggendorff’s Annalen, Fifth Series, Band 9, Ss. 102, et seq. Footnote 76: Pennsylvania Agricultural Experiment Station Report, for 1891, pp. 194, et seq. Footnote 77: Agricultural Science, Vol. 8, pp. 28, et seq. (Correction. For Fig. 13, second line from bottom of page 112, read Fig. 14.) Footnote 78: Haberland. Forschungen auf der Gebiete der Agricultur-Physik, 1878, S. 148. Footnote 79: Grundlagen zur Beurteilung der Ackerkrume, Weimar, 1882. Footnote 80: Vid. supra, 10. Footnote 81: