CLOUDS
TO finish his talk on lightning, the next morning Uncle Paul told them
about clouds. The occasion, moreover, was very favorable. In one part of
the sky great white clouds like mountains of cotton were piled up. The
eye was delighted with the soft outlines of that celestial wadding.
“You remember,” he began, “all those fogs that on damp autumn and winter
mornings cover the earth with a veil of gray smoke, hide the sun, and
prevent our seeing a few steps in front of us!”
“Looking into the air, you could see something like fine dust of water
floating,” said Claire; and Jules added:
“We played hide and seek with Emile in that kind of damp smoke. We could
not see each other a few steps away.”
“Well,” resumed Uncle Paul, “clouds and fog are the same thing; only fog
spreads about us and shows for what it is, gray, damp, cold; while
clouds keep more or less above us and take on, with distance, a rich
appearance. There are some of dazzling whiteness, like those you see
over there; others of a red color, or golden-hued, or like fire; still
others of the color of ashes, and others that are black. The color
changes, too, from moment to moment. At sunset you will see a cloud
begin with being white, then turn scarlet, then shine like a pile of
embers, or like a lake of melted gold, and finally become dull and turn
gray or black, according as the sun’s rays strike it less and less. All
that is a matter of illumination by the sun. In reality, clouds, however
splendid in appearance, are formed of a damp vapor like that of fog. We
can assure ourselves of this by a near approach.”
“People can then mount as high as the clouds, Uncle?” Emile asked.
“Certainly. All one needs is a pair of legs stout enough to climb to the
top of a mountain. Often then clouds are under one’s feet.”
“And you have seen clouds underneath you?”
“Sometimes.”
“That must be a very beautiful sight.”
“So beautiful that words cannot express it. But it is not exactly a
pleasure if the clouds mount and envelop you. You can be very much
embarrassed by the obscurity of the fog alone. You lose your way; you
become confused, without suspecting any danger in the most dangerous
places, at the risk of falling into some abyss; you lose sight of the
guides, who alone know the way and could save you from a false step. No,
all is not roses up among the clouds. You will perhaps learn that some
day to your cost. Meanwhile let us transport ourselves in imagination to
the top of a cloud-capped mountain. If circumstances are favorable, here
is what we shall see:
“Above our heads the sky, perfectly clear, presents no unusual
appearance; the sun shines there in all its brilliancy. Down there at
our feet, almost in the plains, white clouds spread themselves out. The
wind sweeps them before it and drives them toward the summit. There they
are, rolling and mounting up the side of the mountain. One would think
they were immense flocks of cotton pushed up the slope by some invisible
hand. Now and then a ray of sunlight penetrates their depths and gives
them the brilliancy of gold and fire. The beautiful clouds behind which
the sun disappears at its setting are not richer. What brilliant tints,
what soft suppleness! They mount higher and higher. Now they roll up
like a shining white band around the top of the mountain, and hide the
view of the plain from us. Only the point where we are projects above
the cloud-curtain, like an islet above the sea. At last this point is
invaded, we are in the bosom of the clouds. Warm tints, soft outlines,
striking views—all have disappeared. It is now only a dark fog that
saturates with moisture and makes us feel depressed. Ah, if some breath
of wind would make haste and sweep away these disagreeable clouds!
“That, my little friends, is what one does not fail to wish when one is
in the clouds, which, so beautiful at a distance, are nothing but gloomy
fog when close at hand. The spectacle of the clouds should be seen from
afar. When in our curiosity we wish to examine certain appearances too
closely, we sometimes find them deceptive; but we also find that, under
a secondary brilliancy, which serves to adorn the earth, they hide
realities of the first importance. The marvels of the clouds are only an
appearance, an illusion of light; but under this illusion are concealed
the reservoirs of rain, source of the earth’s fecundity. God, by whom
the smallest details of creation have been ordered, willed that the most
common but also most necessary substances should serve as an ornament to
the earth in spite of their really humble aspect; and he clothes them
with a prestige dependent on the distance from which we are to
contemplate them. The gray vapor of the clouds gives us rain. That is
its chief utility. The sun illuminates it, and that suffices to
transform it into a celestial tapestry in which the astonished eye finds
the splendor of purple, gold and fire. That is its ornamental function.
[Illustration: Cirrus]
“The height maintained by clouds is very variable and is generally less
than you might suppose. There are clouds that lazily trail along the
ground; they are the fogs. There are others that cling to the sides of
moderately high mountains, and still others that crown the summits. The
region where they are commonly found is at a height varying from 500 to
1500 meters. In some rather rare instances they rise to nearly four
leagues. Beyond that eternal serenity reigns; clouds never mount there,
thunder never rumbles, and snow, hail, and rain never form.
“Those clouds are called ‘cirrus’ that look sometimes like light flocks
of curly wool, sometimes like drawn-out-filaments of dazzling whiteness,
sharply contrasting with the deep blue of the sky. They are the highest
of all the clouds. They are often a league high. When cirrus clouds are
small and rounded and closely grouped in large numbers, so as to look
like the backs of a flock of sheep, the sky thus covered is said to be
dappled. It is usually a sign that the weather is going to change.
[Illustration: Cumulus]
“The name ‘cumulus’ is given to those large white clouds with round
outlines which pile up, during the heat of summer, like immense
mountains of cotton-wool. Their appearance presages a storm.”
“Then the clouds we see over there next to the mountains,” queried
Jules, “are cumulus? They look like piles of cotton. Will they bring us
a storm?”
“I think not. The wind is driving them in another direction. The storm
always takes place in their neighborhood. There! Hear that!”
A sudden light had just flashed through the flocks of the cumulus. After
rather a long wait the noise of the thunder reached them, but greatly
weakened by distance. Questions came quickly from Jules’s and Emile’s
lips: “Why does it rain over there, and not here? Why does the noise of
the thunder come after the lightning? Why—”
“We are going to talk about all that,” said Uncle Paul; “but first let
us learn the other forms of clouds. ‘Stratus’ is applied to clouds
disposed in irregular bands placed in tiers on the horizon at sunrise or
sunset. They are clouds that, in the fading daylight, especially in
autumn, take the glowing tints of melted metals and of flame. The red
stratus of the morning are followed by rain or wind.
[Illustration: Stratus]
“Finally, we give the name ‘nimbus’ to a mass of dark clouds of a
uniform gray, so crowded together that it is impossible to distinguish
one cloud from another. These clouds generally dissolve into rain. Seen
from a distance, they often look like broad stripes extending in a
straight line from heaven to earth. They are trails of rain.
“Now Emile may ask his questions.”
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