After the block has been cut, it may be moved if the soil is sufficiently compact, and then allowed to dry out in its own formation or elsewhere. The results are most valuable in the first case, though it is often an advantage to remove blocks cut from shade or wet formations to dry, sunny stations where they will dry more rapidly. The most satisfactory and natural method, however, is to leave the block in place, and to prevent the reestablishment of capillary action by enclosing it within plates. This is accomplished by slipping thin sheet-iron plates into position along the cut surfaces. The plate for the bottom should be somewhat wider than the block, and is slipped into place by raising the block if the soil is not too loose; in the latter event, it is carefully driven in. The side plates are then pushed down to meet the former. The size of the plates depends upon the block; in general, plates of 1, 2, and 3 feet square, with the bottom plates a trifle larger, are the most serviceable. Access of rain and dew is prevented by an awning of heavy canvas which projects far enough beyond each side of the block to prevent wetting. The height will depend of course upon the size of the plants. The awning must be used only when rain or heavy dew is threatened, as the shade which it produces changes the power of the plant to draw water from the soil. The time necessary to cause wilting varies with the habitat and the weather. When the block is large and in position, two or three weeks are required. This period of drying incidentally furnishes an excellent opportunity for determining the rate at which the particular soil loses water. The holard sample is taken daily for several days before the block is cut out, in order to obtain an average, care being taken of course to avoid a period of extreme weather. The echard samples are taken as soon as the wilting is sufficient to indicate that the limit of available water is reached. The air-dry soil above the roots is first removed. The treatment of the samples and the computation of the chresard are as previously indicated. =54. Chresard values of different soils.= The following table gives the water-content values of six representative soils. The per cents of holard (at saturation) and of echard are those determined by Hedgcock[3] with six mesophytes as test plants for each soil. The chresard has been computed directly from these. ══════╤═════════╤═════════╤═════════ │ HOLARD │ ECHARD │CHRESARD ──────┼────┬────┼────┬────┼────┬──── Sand │14.3│12.6│ .3│ .25│ 14│12.3 Clay │47.4│32.5│ 9.3│ 6.3│38.1│26.2 Loess │59.3│37.1│10.1│ 6.4│49.2│30.7 Loam │64.1│39.1│10.9│ 6.6│53.2│32.5 Humus │65.3│39.6│11.9│ 7.2│53.4│32.4 Saline│68.5│40.8│16.2│ 9.6│52.3│31.2 ──────┴────┴────┴────┴────┴────┴────