To study river action it is not necessary to visit a river (if there be none near); any small stream of water, any tiny rivulet beside the roadway, tells its story of wearing and building, its vertical cutting and its swinging from side to side. It has its miniature valley, its basin and water-parting and possibly a delta at its mouth. It may also have its cascade or waterfall.
Rivulet Showing Fall of Water and Delta.
The wearing of rock, through the influence of rain, frost and heat, may be seen in any stone building, fence or pavement.
Effects of heat and moisture on vegetation, as influencing the growth of plants and trees, should be noticed. The growth of shrubs and trees during a dry season can be measured and compared with that of wet seasons.
The observer should mark the effect of vegetation in the action of rain on a grassy slope—how the grass protects the soil, preventing it from being washed away, and how, by holding back the water so that it flows more slowly, it is less destructive in its action.
To add to the interest, the pupil may be led to imagine the effects upon climate and streams, of the denuding of large areas of their forests; also how rock sculpturing, in the forming of gorges, cañons, etc., would be modified by the volume and force of streams.
Observation should also be made on the making of soils, their constituents and relative proportions of loam, sand, gravel and clay, and the relation of these to plant and animal life.
The part that the common earth-worm bears in constantly uniting, enriching and otherwise preparing the soils for the support of vegetable life, may be seen in many areas. (It has been computed that in one year several tons of soil are brought up and distributed by them, within an area of an acre of land.)
A study made of the action of underground water, as shown in common and intermittent springs, would be full of interesting suggestions.