226 
THE FORMATION OF GLACIERS. 
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, hut, 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 open- 
ing 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 
