Chapter Vi.--Sunlight and Shadow.

We have heat again, and now as an elementary lesson in the distribution of sunshine. Children love to observe continual changes. The shadow is an object of interest. It has an element of mystery about it which borders upon the supernatural. Children observe spontaneously the long shadows of morning and the lengthening shadows of the descending sun. Most farm boys can tell the moment of noon by their shadows.

These are all steps in the more difficult problems of lengthening and shortening shadows that mark the changing seasons, and that lead to the theories of the earth's rotation and revolution. Day by day children should note the changes of slant upon the shadow stick which they can easily make for themselves.