tood on
the summit of the Jungfrau when a frozen cloud filled the air with
ice-needles, while I could see the same cloud pouring down sheet of rain
upon Lauterbrunnen below. I remember this spectacle as one of the most
impressive I have witnessed in my long experience of Alpine scenery. The
air immediately about me seemed filled with rainbow-dust, for the
ice-needles glittered with a thousand hues under the decomposition of
light upon them, while the dark storm in the valley below offered a
strange contract to the brilliancy of the upper region in which I stood.
One wonder where even so much vapor as may be transformed into the
finest snow should come from at such heights. But the warm winds,
creeping up the sides of the valleys, the walls of which become heated
during the middle of the day, come laden with moisture which is changed
to a dry snow like dust as soon as it comes into contact with the
intense cold above.

Currents of warm air affect the extent of the glaciers, and influence
also the line of perpetual snow, which is by no means at the same level
even in neighboring localities. The size of glaciers, of course,
determines to a great degree the height at which they terminate, simply
because a small mass of ice will melt more rapidly, and at a lower
temperature, than a larger one. Thus, the small glaciers, such as those
of the Rothhorn or of Trift, above the Grimsel, terminate at a
considerable height above the plain, while the Mer de Glace, fed from
the great snow-caldrons of Mont Blanc, forces its way down to the bottom
of the valley of Chamouni, and the glacier of Grindelwald, constantly
renewed from the deep reservoirs where 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 considerabl