dark, and those that were shaded may
all at once glow in the rays of the sun. Again, the appearance of a
cloud, with respect to the sun, may entirely alter its character. The
same cloud, to one observer, may appear entirely in shade, to another
tipped with silver; to a third it may present brilliant points and
various degrees of shade, or one of its edges only may appear
illuminated; sometimes the middle parts may appear in shadow, while the
margin may be partially luminous, rendering the middle parts all the more
obscure by the contrast.

A wonderful variety may also be produced by the shadow of one cloud
falling upon another. The accompanying sketch furnishes an example of
this. Sometimes the whole of a cloud projects a shadow through the air
upon some other far distant cloud, and this again upon another, until at
length it reaches the ground. The shadows of moving clouds may often be
traced upon the ground, and they contribute greatly to modify the
appearance of the landscape. A large number of small flickering clouds
produce broken lights and shades which have an unpleasant jarring effect;
but when the clouds are massive, or properly distributed, the shadows
often produce a high degree of repose.

[Picture: Shadows of clouds]

Clouds are often seen to advantage in mountainous countries. Here the
aspect of the heavens may be entirely different at different elevations.
A single cloud in the valley may conceal the whole of the upper sky from
an observer; but as he ascends he may gradually get above this and other
layers or bands of cloud, and see a beautifully variegated sky above him,
while the clouds which conceal the valley may be rolling at his feet.
Evelyn, in his Memoirs, notices a scene of this kind. He says,--"Next
morning we rode by Monte Pientio, or, as vulgarly called, Monte
Mantumiato, which is of an excessive height, ever and anon peeping above
airy clouds with its snowy head, till we had climbed to the inn at
Radicofany, built by Ferdinand the greate Duke for the necessary
refreshment of travellers in so inhospitable a place. As we ascended we
entered a very thick, solid, and dark body of cloudes, which looked like
rocks at a little distance, which lasted neare a mile in going up; they
were dry, misty vapours, hanging undissolved for a vast thicknesse, and
obscuring both sun and earth, so that we seemed to be in the sea rather
than in the cloudes, till, having pierced th