Page:The fairy tales of science.djvu/117



the Sunbeam falls we find life and motion; elsewhere, death and stillness. Under its influence the seed germinates, the stem sends forth branches, the leaf bursts from the bud, the flower unfolds its petals, and the fruit grows and ripens.

This subtle agent plays an important part in many of the fairy tales of science. The philosopher has conducted it into his dark laboratory, and by twisting and torturing it with cunningly-devised instruments, has forced it to reveal so many wonderful truths, that the mind, in attempting to grasp them, is fairly bewildered. The Magic of the Sunbeam is indeed an inexhaustible theme, and we can only touch upon a few of its mysteries.

Every sunbeam consists of light, heat, and chemical power, or actinism. At present we will consider the sunbeam as a ray of light, without regarding its other principles.

What is light? This is one of those