SECTION IV. HOW THE WATER RISES IN THE SOIL
Fig. 8. Using Lamp-Chimneys
To show the Rise of Water in Soil
When the hot, dry days of summer come, the soil depends upon the subsoil, or undersoil, for the moisture that it must furnish its growing plants. The water was stored in the soil during the fall, winter, and spring months when there was plenty of rain. If you dig down into the soil when everything is dry and hot, you will soon reach a cool, moist undersoil. The moisture increases as you dig deeper into the soil.
Now the roots of plants go down into the soil for this moisture, because they need the water to carry the plant food up into the stems and leaves.
You can see how the water rises in the soil by performing a simple experiment.
EXPERIMENT
Take a lamp-chimney and fill it with fine, dry dirt. The dirt from a road or a field will do. Tie over the smaller end of the lamp-chimney a piece of cloth or a pocket handkerchief, and place this end in a shallow pan of water. If the soil in the lamp-chimney is clay and well packed, the water will quickly rise to the top.
By filling three or four lamp-chimneys with as many different soils, the pupil will see that the water rises more slowly in some than in others.
Now take the water pan away, and the water in the lamp-chimneys will gradually evaporate. Study for a few days the effect of evaporation on the several soils.