What can we do for our sandy soils to give them greater power to take moisture from below? For immediate results we can compact them by rolling or packing. This brings the particles closer together, makes the spaces between them smaller, and therefore allows the water to climb higher. For more lasting results we can fill them with organic matter in the shape of stable manures or crops turned under. Clay may be used, but is expensive to haul. Which soils have greatest power to hold the water which enters them? =Experiment.=--Use the same or similar apparatus as for the last experiment. After placing the cloth caps over the ends of the tubes label and carefully weigh each one, keeping a record of each; then fill them with the dry soils and weigh again. Now place the tubes in the rack and pour water in the upper ends until the entire soil is wet; cover the tops and allow the surplus water to drain out; when the dripping stops, weigh the tubes again, and by subtraction find the amount of water held by the soil in each tube; compute the percentage. It will be found that the organic matter will hold a much larger percentage of water than the other soils; and the clay more than the sand. The tube of organic soil will actually hold a larger amount of water than the other tubes. (See also Fig. 25.) In the experiment on page 40 we noticed that the sand took in the water poured on its surface and let it run through very quickly. This is a fault of sandy soils. What can we do for our sandy soils to help them to hold better the moisture which falls on them and tends to leach through them? For immediate effect we can close the pores somewhat by compacting the soil with the roller. For more lasting effects, we can fill them with organic matter. Which soils will hold longest the water which they have absorbed? Or which soils will keep moist longest in dry weather? [Illustration: FIG. 23. To show how bottles may be used in place of lamp chimneys shown in Figs 22 and 24.] [Illustration: FIG. 24.--CAPILLARITY OF SOILS To show the relative powers of soils to take water from below.] [Illustration: FIG. 25.--WATER-ABSORBING AND WATER-HOLDING POWERS OF SOILS.] =Experiment.=--Fill a pan or bucket with moist sand, another with moist clay, and a third with moist organic matter; set them in the sun to dry and notice which dries last. The organic matter will be found to hold moisture much longer than the other soils. The power of the other soils to hold moisture through dry weather can be improved by mixing organic matter with them. We find then that the power of soils to absorb and hold moisture depends on the amount of sand, clay, or humus which they contain, and the compactness of the particles. We see also how useful organic matter is in improving sandy and clayey soils. THE EFFECT OF WORKING SOILS WHEN WET