Among the Alps and other snow-capped mountains, these sunset and sunrise phenomena assume a particularly beautiful form, known as the _Alpenglow_. In fine weather, just before sunset, the peaks to the eastward begin to show a reddish or golden hue. This fades gradually, but in a few minutes, when the sun is a little below the horizon of the observer, but the peaks themselves are still bathed in direct sunlight, an intense red glow, beginning down the slopes, moves upward to the summits. This is identical with the antitwilight arch described above. Presently this glow is succeeded by an ashy tint, as the peaks are immersed in the rising shadow of the earth (the dark segment). Their rocks and snows assume a livid appearance, aptly described by the inhabitants of Chamonix, whence the phenomena in question are well seen on the summit of Mont Blanc, as the _teinte cadavéreuse_. In ordinary weather darkness succeeds without any further notable phenomena, but occasionally there occurs a remarkable renewal of rosy light upon the peaks, known as the _recoloration_ or _afterglow_. At Chamonix this is termed the “resurrection of Mont Blanc.” The afterglow has been variously explained, but it is probably due, mainly at least, to the reflection of the purple light in the western sky. Sometimes it lasts until an hour after sunset, and it passes away from below upward. On very rare occasions there is a second afterglow, presumably the reflection of the second purple light mentioned above. Similar phenomena are often seen in reverse order at sunrise. A pretty phenomenon observed chiefly in the late afternoon and early morning consists of beams of light radiating from the sun, known technically as _crepuscular rays_. The beams are made visible by the presence of abundant dust or water droplets in the atmosphere, and the intervening dark spaces are the shadows of clouds. When the sun is above the horizon and the beams are directed downward, the phenomenon is popularly described as “the sun drawing water” and is regarded as a sign of rain. Sailors call these beams the “backstays of the sun,” and they have several other names based upon the legendry associated with them in different parts of the world. After sunset or before sunrise a fanlike sheaf of the beams often extends upward from the western or eastern horizon, respectively. The Homeric expression “rosy-fingered dawn” probably refers to this phenomenon. In all cases the apparent divergence of these beams is an effect of perspective, as they are really parallel. A rarer phenomenon is that of _anticrepuscular rays_, which appear to converge to a point opposite the sun. In this case the beams and shadows are projected entirely across the sky, but their paths can very seldom be traced in the upper part of the heavens because in this direction the observer’s line of sight passes through a comparatively shallow extent of dusty atmosphere.