"A loud peal of thunder was heard; and shortly after I observed that a strange singing sound, like that of a kettle, was issuing from my alpenstock. We halted, and finding that all the axes and stocks emitted the same sound, stuck them into the snow. The guide from the hotel now pulled off his cap, shouting that his head burned; and his hair was seen to have a similar appearance to that which it would have presented had he been on an insulated stool under a powerful electrical machine. We all of us experienced the sensation of pricking and burning in some part of the body, more especially in the head and face, my hair also standing on end in an uncomfortable but very amusing manner. The snow gave out a hissing sound, as though a heavy shower of hail were falling; the veil on the wide-awake of one of the party stood upright in the air; and on waving our hands, the singing sound issued loudly from the fingers. Whenever a peal of thunder was heard, the phenomenon ceased, to be resumed before its echoes died away. At these times we felt shocks, more or less violent, in those portions of the body which were most affected. By one of these shocks my right arm was paralysed so completely that I could neither use nor raise it for several minutes, nor indeed until it had been severely rubbed; and I suffered much pain in it at the shoulder-joint for some hours." The successive layers of snow which fall on the mountains do not remain there for ever. Unless got rid of in some way their thickness would mount up to an enormous extent. It is reckoned that on the Alps the average yearly fall of snow is thirty-three feet. In the course of a century, therefore, the height of these mountains would be increased by 3,300 feet, which we know is not the case. Various causes prevent its accumulating, among which we may mention the powerful influence of the sun's rays, the evaporation promoted by the atmosphere, the thawing influence of rain and mist, avalanches, and lastly, which is perhaps the most important, the fact that the snow composing the snowfields, as they are called, of the high regions slowly creeps down towards the valleys, where they move along as glaciers, the ends of which are gradually melted away by the warm air surrounding them, and thus the muddy glacier-streams are originated. Few perils are more dreaded by the inhabitant of the Alps than those of the avalanches. The particular way in which each avalanche descends is varied according to the shape of the mountain, the condition of the snow, and the time of the year. Hence there are three different kinds of avalanche. First, there is the ice-avalanche. The smaller glaciers, which, in the Alps, cling to the upper slopes of the higher mountains, frequently terminate abruptly on the edge of some precipice. Thus the ice, urged on by the pressure of the masses above it, moves forward until it plunges over and