he shadows here described of course is caused only
by that of the dingles they cross; but I have not in any of my
books yet dwelt enough on the difference of character between the
dipping and the mounting winds. Our wildest phase of the west wind
here at Coniston is 'swallow-like' with a vengeance, coming down on
the lake in swirls which spurn the spray under them as a fiery
horse does the dust. On the other hand, the softly ascending winds
express themselves in the grace of their cloud motion, as if set to
the continuous music of a distant song.[C]

The reader will please note also that whenever, either in 'Modern
Painters' or elsewhere, I speak of rate of flight in clouds, I am
thinking of it as measured by the horizontal distance overpast in
given time, and not as apparent only, owing to the nearness of the
spectator. All low clouds appear to move faster than high ones, the
pace being supposed equal in both: but when I speak of quick or
slow cloud, it is always with respect to a given altitude. In a
fine summer morning, a cloud will wait for you among the pines,
folded to and fro among their stems, with a branch or two coming
out here, and a spire or two there: you walk through it, and look
back to it. At another time, on the same spot, the fury of
cloud-flood drifts past you like the Rhine at Schaffhausen.

The space even of the doubled lecture does not admit of my entering
into any general statement of the action of the plague-cloud in
Switzerland and Italy; but I must not omit the following notes of
its aspect in the high Alps.

"SALLENCHES, _11th September, 1882_.

This morning, at half-past five, the Mont Blanc summit was clear,
and the greater part of the Aiguilles du Plan and Midi clear
dark--all, against pure cirri, lighted beneath by sunrise; the sun
of course not visible yet from the valley.

By seven o'clock, the plague-clouds had formed in _brown_ flakes,
down to the base of the Aiguille de Bionassay; entirely covering
the snowy ranges; the sun, as it rose to us here, shone only for
about ten minutes--gilding in its old glory the range of the
Dorons,--before one had time to look from peak to peak of it, the
plague-cloud formed from the west, hid Mont Joli, and steadily
choked the valley with advancing streaks of dun-colored mist.
Now--twenty minutes to nine--there is not _one ray_ of sunshine on
the whole valley, or on its mountains, from the Forclaz down to
Cluse.