ont, or to the crupper behind, leaving its master in a situation not
to be envied."

[Picture: Mists in the Valley]

CHAPTER III.

VARIOUS FORMS OP CLOUDS--THE CIRRUS, OR CURL-CLOUD--THE CUMULUS, OR
STACKEN-CLOUD--THE STRATUS, OR FALL-CLOUD--THE CIRRO-CUMULUS, OR
SONDER-CLOUD--THE CIRRO-STRATUS, OR WANE-CLOUD--THE CUMULO-STRATUS, OR
TWAIN-CLOUD--THE NIMBUS, OR RAIN-CLOUD--ARRANGEMENT OF
RAIN-CLOUDS--APPEARANCES OF A DISTANT SHOWER--SCUD--CAUSE OF
RAIN--FORMATION OF CLOUDS--MISTS--HEIGHTS OF CLOUDS--APPEARANCE OF THE
SKY ABOVE THE CLOUDS.

Many persons are apt to suppose that the clouds are among the most fitful
and irregular appearances in the world; fleeting and unstable in their
nature, uncertain in their forms, apparently subject to no fixed laws,
and obedient neither to times nor seasons. Attentive observers, however,
have proved that the beauty and harmony which are everywhere found to
prevail in nature when rightly understood, can also be traced, even in
the clouds. Although very much still remains to be discovered respecting
them, yet it is found that, like all the other natural productions, they
admit of being arranged and classified. So obvious was this to persons
whose interest it is to observe the weather, that, long before scientific
men had studied the subject, country people had noticed the different
forms of clouds, and had learned to distinguish them by different names.

The first scientific man who made the clouds the object of his particular
study, was Luke Howard, who, from an attentive consideration of their
forms and appearances, found that they might all be arranged under three
simple or primary forms, namely:--

1. The _Cirrus_--so called from its resemblance to a _curled lock of
hair_. (Figures, 1, 2; page 77.)

2. The _Cumulus_, from the _heaped_ appearance presented by the convex
masses which form this cloud. (Figure 7.)

3. The _Stratus_, from its spreading out horizontally in a continuous
layer, and increasing from below. (Figure 10.)

These three primary forms are subject to four modifications:--

The first is the _Cirro-cumulus_, consisting of small roundish and
well-defined masses, in close horizontal arrangement. (Figure 3.)

[Picture: Various forms of clouds]

The second is the _Cirro-Stratus_, and the masses which compose it are
small and rounded, but thinned off towards a part, or towards the whole
of their circu