Snow-flakes have been also found in the form of regular hexagons and other plane figures, as well as in cylinders and spheres.
As a general rule, the intenser the cold the more perfect the formation, and the most perfect specimens are Arctic or Alpine in their locality.
In this climate the snow seldom falls when the mercury is much below zero; but the slightest atmospheric changes may alter the whole condition of the deposit, and decide whether it shall sparkle like Italian marble, or be dead-white, like the statuary marble of Vermont,—whether it shall be a fine powder that can sift through wherever dust can, or descend in large, woolly masses, tossed like mouthfuls to the hungry earth.
The most remarkable display of crystallization which I have ever seen was on the 13th of January, 1859.
There had been three days of unusual cold, but during the night the weather had moderated, and the mercury in the morning stood at +14°. About two inches of snow had fall