National Geographic : 1923 Jan
THE MAGIC BEAUTY OF SNOW AND DEW BY WILSON A. BENTLEY With Illustrationsfrom Photographs by the Author WATER plays an all-important and most beneficent part in Nature's plan. Numerous bulky volumes might be written telling of its many roles in nearly all the activities oc curring upon the Earth. It might prop erly be called the "life-giving fluid," for life in any form is not possible without it. However profoundly one may be im pressed by the vast tasks that water per forms, one is almost equally impressed and amazed at the marvelous beauty and diversity of its forms-in clouds, snow, frost, ice, dew, rain, rivers, waterfalls, lakes, and glaciers. And these are not only beautiful in themselves, but many of them, as snow, frost, and dew, collect upon and beautify various natural objects. The dew and hoarfrost add rarest love liness to vegetation and to various objects, while a snowfall changes the aspect of Nature over vast areas, imparting chaste beauty to forests, mountains, and plains. WATER FORMS ARE DEPENDENT ON TEMPERATURE The form that water assumes, whether fluid or solid, depends largely upon its temperature. Water molecules possess poles, negative and positive, which tend to draw them together in certain align ments forming solids (crystal forms) ; but most of them (all those forming fluid water) are so disturbed by heat that they dart about rapidly among themselves, making it impossible for them to unite. But when they attain a relative degree of quietude, under conditions of cold, their poles draw them together, and they remain fixed, pole to pole, in regular order. The number and arrangement of the molecules in crystals determine their form, whether hexagonal, pentagonal, or otherwise. A crystallographic law decrees that crys tals which grow rapidly-the branching snowflakes, for example-tend to assume branching forms; conversely, those that grow slowly, in a greater degree of cold, tend to assume solid forms. Dew is one of the most common forms of fluid water formation, though jointly with the hoarfrost it is one of the least as regards quantity. It is largely a night time phenomenon, because only then can the water molecules in the air become quiet enough to gather and remain in a "swarm" upon vegetal and other objects. The dew forms in such a gentle and unobtrusive way that it fails to impress the student, as do many other water forms. Although dewdrops, like raindrops, lack variety of form, they exhibit much variety of arrangement on plant leaves and other objects. The myriads of opalescent, iri descent drops sparkling over meadow and hillside of a dewy morning create one of Nature's loveliest effects. Dewdrops col lect beautifully upon grass blades, straw berry and clover leaves; but the dew-laden geometrical webs of the garden spider are lovely beyond description and form the masterpieces of dewy art (see pages Ino and III). Hoarfrost is, perhaps, the least, as re gards quantity, among the main divisions of water forms; yet it provides a world of beauty and diversity. It forms in the open on cold, calm nights, when the tem perature goes below the freezing point of water. When the deposits are copious, all outdoor Nature is converted into. a fairyland rivaling that produced by an ice storm. Yet the real masterpieces of the frost are wrought indoors in the winter time, upon our window-panes in cold rooms, where all can see and admire them. The tiny molecular artists create an infinite variety of shapes, suggesting trees, ferns, coral, lace, starry firmaments, tropical forest effects, and castles (pp. 108-109). SNOW CRYSTALS Of all the forms of water, however, the tiny six-pointed crystals of ice called snow, that form in such quantities within the clouds during storms, are incompar ably the most beautiful and varied.