Page:Popular Science Monthly Volume 45.djvu/48

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ward and upward again from the ground, struck the one-story wall D.

Fig. 9 shows a section of the wall D in the beginning of that storm. Unfortunately, the other negatives of that group were spoiled.

On C the deposits on cornice and weatherboards nearest D partook of the shape and direction of those on D; and the same

PSM V45 D048 Winter windstorm effect on wood exterior.jpg
Fig. 9.

was true of those nearest B. In the space intervening, the frost was laid on obliquely, resembling the first course of a heavy lattice. All these walls, as well as all others on the mountain top which faced the west and north, were completely covered, and presented the appearance of exquisitely chiseled marble.

On all flat surfaces, whether curved or rectilinear in outline, when they are suspended vertically, faced to the wind, so that it may blow past all sides unobstructed, the frost-forms lie at an angle of thirty degrees to the surface, with their bases to its edges, and point accurately toward the center.

On a flat surface having a rim that projects as much as half an inch, they are built on the inner edge of the rim, and extend toward the center at a right angle to the rim and parallel to the surface. When the rim is more shallow, their bases are set in the angle where the rim joins the surface, and they stand out from the surface at an angle of more than thirty degrees.

Fig. 10 is the lid of a cream freezer, showing frost-forms point-