The narrow Alpine zone of peaks and snow that forms the crest of the Rocky Mountains has its own individual elemental moods, its characteristic winds, its electrical and other peculiarities, and a climate of its own. Commonly its days are serene and sunny, but from time to time it has hail and snow and showers of wind-blown rain, cold as ice-water. It is subject to violent changes from clear, calm air to blizzard. I have enjoyed these strange, silent heights in every season of the year. In climbing scores of these peaks, in crossing the passes, often on snowshoes, and in camping here and there on the skyline, I have encountered these climatic changes and had numerous strange experiences. From these experiences I realize that the transcontinental aviator, with this realm of peak and sky, will have some delightful as well as serious surprises. He will encounter stern conditions. He may, like a storm-defying bird, be carried from his course by treacherous currents and battle with breakers or struggle in vain in the monstrous, invisible maelstroms that beset this ocean of air. Of these skyline factors the more imposing are wind, cold, clouds, rain, snow, and subtle, capricious electricity. High winds are common across the summits of these mountains; and they are most prevalent in winter. Those of summer, though less frequent and much more short-lived, are a menace on account of their fury and the suddenness with which they surprise and sweep the heights. Early one summer, while exploring a wide alpine moorland above the timber-line, I--and some others--had an experience with one of those sudden stormbursts. The region was utterly wild, but up to it straggling tourists occasionally rode for a view of the surrounding mountain world. All alone, I was studying the ways of the wild inhabitants of the heights. I had spent the calm, sunny morning in watching a solitary bighorn that was feeding among some boulders. He was aged, and he ate as though his teeth were poor and walked as though afflicted with rheumatism. Suddenly this patriarch forgot his age and fled precipitately, with almost the speed of frightened youth. I leaped upon a boulder to watch him, but was instantly knocked headlong by a wild blast of wind. In falling I caught sight of a straw hat and a wrecked umbrella falling out of the sky. Rising amid the pelting gale of flung hail, ice-water, and snow, I pushed my way in the teeth of the storm, hoping for shelter in the lee of a rock-pile about a hundred yards distant. A lady's disheveled hat blew by me, and with the howl of the wind came, almost drowned, excited human utterances. Nearing the rock-pile, I caught a vague view of a merry-go-round of man and horse, then a glimpse of the last gyration, in which an elderly Eastern gentleman parted company with a stampeded bronco.