Page:Popular Science Monthly Volume 45.djvu/51

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39
FROST-FORMS ON ROAN MOUNTAIN.

I watched throughout the winter for the stellar and hexagonal snowflakes, but never found them while the clouds enveloped the mountain. The particles of frozen vapor in the clouds resemble finely ground meal. When a cloud rises from fifteen to

PSM V45 D051 Frost formation in lower temperature range.jpg

Fig. 13.

twenty feet above any given place, several of these particles (usually six or eight) come down joined together like beads on a pin; when it rises fifty or a hundred feet, the little sticks of globules cross and adhere to each other in falling, and reach the earth in all the complex shapes commonly called snow crystals.





Nothing escapes the ravages of insects, not even books. One of the insect "enemies of books" is the Lepisma saccharina, often called the silver fish, which is marked by its luster and its activity. Prof. Westwood once named a minute beetle, which had done much mischief to the cover of a book, Hypothenemus erudites. Specimens of books damaged by insects are exhibited in the South Kensington Museum, London. Mr. Zaehnsdorf, a bookbinder, has formed a collection of the book pests which he has met in the exercise of his calling. The Arabs are said to write sometimes the name Kabikaj, the name of a genius who presides over insects, on their manuscripts, in order to protect them from the ravages of his subjects.