and south sides is due not so much to the winter sunshine as to the heat
of the preceding summer, stored up in the rocks, which rapidly melts the
snow in contact with them. For though summer sun-heat is stored in the
rocks of the south side also, the amount is much less because the rays
fall obliquely on the south wall even in summer and almost vertically
on the north.

The upper branches of the Yosemite streams are buried every winter
beneath a heavy mantle of snow, and set free in the spring in
magnificent floods. Then, all the fountains, full and overflowing, every
living thing breaks forth into singing, and the glad exulting streams
shining and falling in the warm sunny weather, shake everything into
music making all the mountain-world a song.

The great annual spring thaw usually begins in May in the forest region,
and in June and July on the high Sierra, varying somewhat both in time
and fullness with the weather and the depth of the snow. Toward the end
of summer the streams are at their lowest ebb, few even of the strongest
singing much above a whisper they slip and ripple through gravel and
boulder-beds from pool to pool in the hollows of their channels, and
drop in pattering showers like rain, and slip down precipices and fall
in sheets of embroidery, fold over fold. But, however low their singing,
it is always ineffably fine in tone, in harmony with the restful time of
the year.

The first snow of the season that comes to the help of the streams
usually falls in September or October, sometimes even is the latter part
of August, in the midst of yellow Indian summer when the goldenrods and
gentians of the glacier meadows are is their prime. This Indian-summer
snow, however, soon melts, the chilled flowers spread their petals to