There are no accidents in Nature. Every motion of the constantly shifting bodies in the world is timed to the occasion for some definite, fore-ordered end. The flowers blossom in obedience to the same law that marks the course of constellations, and the song of a bird is the echo of a universal symphony. Nature is one, and to me the greatest delight of observation and study is to discover new unities in this all-embracing and eternal harmony.