falls from it, but in moderation. If
there be large masses of scud running beneath it for its drops to fall
through (especially as is sometimes the case, in two or more currents),
the rain may be very heavy. But more of this hereafter.

[Illustration: Fig. 10.]

The annexed cut shows the forming stratus, light and thin, passing to the
east, as indicated by the short arrows just before a storm, while the scud
beneath is running to the west.

It was copied from a daguerreotype view, facing northwardly.

Intermediate between the fibrous, tufted, cirrus, and the smooth uniform
stratus, there is a variety of forms partaking more or less of the
character of one or the other, and termed _cirro-stratus_. No single
correct representation of cirro-stratus as a distinct cloud, can be
given--but several varieties will be hereafter alluded to, under the head
of prognostics. Several modifications are represented with tolerable
accuracy upon the cuts.

The cirro-cumulus is a collection in patches of very small distinct heaps
of white clouds; they are called fleecy clouds, from their resemblance to
a collection of fleeces of wool, and are imperfectly represented on the
general cut. They do not appear often, and are usually _fair-weather
clouds_.

This form has none of the characteristics of the cumulus, and does not
appear in the same stratum. It was probably called cumulus because its
small masses are distinct, as are those of the ordinary cumulus. It occurs
in the same stratum as cirro-stratus, and properly belongs to that
modification. I retain the name inasmuch as the cloud is of some practical
importance.

The cumulo-stratus is seldom seen in our climate, as it is represented in
the cut. Stratus condensation _above_, and in connection with cumulus
condensation, is not uncommon, but that precise form is rare.

This, too, is practically of no consequence, and I shall take no further
notice of it.

Recapitulating, I give (in a tabular form) the three principal strata and
their modifications, located with sufficient accuracy for illustration.
The clouds which are found in an upper or lower portion of a stratum are
so represented by the location of their names; those which appear at all
heights in the stratum, with the names across. The elevation is the
average one--although there is no limit to the cirrus above, except the
absence of sufficient moisture. It was seen by Guy Lussac, and has been by
other aeronauts, at an