57 I have already had occasion to mention the rapid changes which occur in the weather at considerable elevations in the Alps, and shall have to do so again in subsequent chapters. No one can regret more than myself the variable weather which afflicts that otherwise delightful chain of mountains, or the necessity of speaking about it: its summits appear to enjoy more than their fair share of wind and tempests. Meteorological disturbances, some would say, are by no means necessary accompaniments of high regions. There are some happy places which are said to be favoured with almost perpetual calm. Take the case of the Sierra Nevada of California, for example, which includes numerous summits from 13,000 to 15,000 feet. Mr. Whitney, of San Francisco, says (in his _Guide-book to the Yosemite Valley, and the adjacent region_), “At high altitudes, all through the mountains, the weather during the summer is almost always the finest possible for travelling. There are occasional storms in the high mountains; but, in ordinary seasons, these are quite rare, and one of the greatest drawbacks to the pleasure of travelling in the Alps, the uncertainty of the weather, is here almost entirely wanting.” It is probable that a more thorough acquaintance with that region will modify this opinion; for it must be admitted that it is very difficult to judge of the state of the atmosphere at great heights from the valleys, and it often occurs that a terrific storm is raging above when there is a dead calm below, at a distance perhaps of not more than three or four miles. A case of this kind is described in Chapter VI., and another may be mentioned here. At the very time that I was regarding the Dent Blanche from a height of 12,550 feet on the Matterhorn, Mr. T. S. Kennedy was engaged in making the first ascent of the former mountain. He described his ascent in a very picturesque paper in the _Alpine Journal_ (1863), and I learn from it that he experienced severe weather. “The wind roared over our ridge, making fearfully wild music among the desolate crags.... It rendered an ordinary voice inaudible,” and “nothing at a distance greater than fifty yards could be seen at all.... Thick mists and driving clouds of snow swept over and past us;” the thermometer fell to 20° Fahr., and his companion’s hair became a mass of white icicles. Now, at this time, Mr. Kennedy was distant from me only four and a half miles. With me, and in my immediate neighbourhood, the air was perfectly calm, and the temperature was agreeably warm; even during the night it fell only two or three degrees below freezing-point. During most of the day the Dent Blanche was perfectly unclouded, though, for a time, light