e portions veiled by the banners, and
how delicately their sides are streaked with snow, where it has come to
rest in narrow flutings and gorges. Mark, too, how grandly the banners
wave as the wind is deflected against their sides, and how trimly each
is attached to the very summit of its peak, like a streamer at a
masthead; how smooth and silky they are in texture, and how finely their
fading fringes are penciled on the azure sky. See how dense and opaque
they are at the point of attachment, and how filmy and translucent
toward the end, so that the peaks back of them are seen dimly, as though
you were looking through ground glass. Yet again observe how some of the
longest, belonging to the loftiest summits, stream perfectly free all
the way across intervening notches and passes from peak to peak, while
others overlap and partly hide each other. And consider how keenly every
particle of this wondrous cloth of snow is flashing out jets of light.
These are the main features of the beautiful and terrible picture as
seen from the forest window; and it would still be surpassingly glorious
were the fore- and middle-grounds obliterated altogether, leaving only
the black peaks, the white banners, and the blue sky.

Glancing now in a general way at the formation of snow-banners, we find
that the main causes of the wondrous beauty and perfection of those we
have been contemplating were the favorable direction and great force of
the wind, the abundance of snow-dust, and the peculiar conformation of
the slopes of the peaks. It is essential not only that the wind should
move with great velocity and steadiness to supply a sufficiently copious
and continuous stream of snow-dust, but that it should come from the
north. No perfect banner is ever hung on the Sierra peaks by a south
wind. Had the gale that day blown from the south, leaving other
conditions unchanged, only a dull, confused, fog-like drift would have
been produced; for the snow, instead of being spouted up over the tops
of the peaks in concentrated currents to be drawn out as streamers,
would have been shed off around the sides, and piled down into the
glacier wombs. The cause of the concentrated action of the north wind is
found in the peculiar form of the north sides of the peaks, where the
amphitheaters of the residual glaciers are. In general the south sides
are convex and irregular, while the north sides are concave both in
their vertical and horizontal sections; the wi