the Jungfrau hoards her vast supplies of snow, descends to about four thousand feet above the sea-level.  But the glacier of the Aar, though also very large, comes to a pause at about six thousand feet above the level of the sea; for the south wind from the other side of the Alps, the warm sirocco of Italy, blows across it, and it consequently melts at a higher level than either the Mer de Glace or the Grindelwald.  It is a curious fact, that in the valley of Hassli the temperature frequently rises instead of falling as you ascend; at the Grimsel, the temperature is at times higher than at Meyringen below, where the warmer winds are not felt so directly.  The glacier of Aletsch, on the southern slope of the Jungfrau, and into which many other glaciers enter, terminates also at a considerable height, because it turns into the valley of the Rhone, through which the southern winds blow constantly.

Under ordinary conditions, vegetation fades in these mountains at the height of six thousand feet, but, in consequence of prevailing winds, and the sheltering influence of the mountain-walls, there is no uniformity in the limit of perpetual snow and ice.  Where currents of warm air are very constant, glaciers do not occur at all, even where other circumstances are favorable to their formation.  There are valleys in the Alps far above six thousand feet which have no glaciers, and where perpetual snow is seen only on their northern sides.  These contrasts in temperature lead to the most wonderful contrasts in the aspect of the soil; summer and winter lie side by side, and bright flowers look out from the edge of snows that never melt.  Where the warm winds prevail, there may be sheltered spots at a height of ten or eleven thousand feet, isolated nooks opening southward where the most exquisite flowers bloom in the midst of perpetual snow and ice; and occasionally I have seen a bright little flower with a cap of snow over it that seemed to be its shelter.  The flowers give, indeed, a peculiar charm to these high Alpine regions.  Occurring often in beds of the same kind, forming green, blue or yellow patches, they seem nestled close together in sheltered spots, or even in fissures and chasms of the rock, where they gather in dense quantities.  Even in the sternest scenery of the Alps some sign of vegetation lingers; and I remember to have found a tuft of lichen growing on the only rock which pierced through the ice on the summit of the Jungfrau.  The absolute solitude, the intense stillness of the upper Alps is most impressive; no cattle, no pasturage, no bird, nor any sound of life,—­and, indeed, even if there were, the rarity of the air in these high regions is such that sound is hardly transmissible.  The deep repose, the purity of aspect of every object, the snow, broken only by ridges of angular rocks, produce an effect no less beautiful than solemn.  Sometimes, in the midst of the wide expanse, one comes upon a patch of the so-called red snow of the Alps.