of clouds as
designated by Howard. They are copied from the engravings in the sixth
edition of Maury's "Sailing Directions."

[Illustration: Fig. 5.]

[Illustration: Fig. 6.]

Figure 5.
The cirrus is indicated by 1 bird.
The cirro-cumulus by 2 "
The cirro-stratus by 3 "
The cumulo-stratus by 4 "

Figure 6.
The cirrus by 1 "
The cumulus by 3 "
The stratus by 2 "
The nimbus by 4 "

How far these representations correspond with the actual appearance of the
different compound forms in England, I can not say. But although they
convey a _general_ idea, _they are not sufficiently accurate for practical
illustration or observation here_. Indeed Howard himself has omitted from
his last edition his plate of the clouds, assigning as a reason, "that the
real student will acquire his knowledge in a more solid manner by the
observation of nature, without the aid of drawings, and that the _more
superficial are liable to be led into error by them_." The collection of
forms in the cuts _does not contain some very important ones_, and
contains some which are not distinct forms; but they may aid us somewhat
in this inquiry, and, therefore, I have copied them. It is well, also, for
the reader to have the generally received description before him.

But for the purpose of _practical_ illustration hereafter, and greater
precision, I shall follow a somewhat different order in describing them,
and introduce two forms of _scud_ quite as important, practically, as any
other.

First, then, commencing at the earth, we have what may be properly termed
_fog_, or low fog. This forms, in still clear weather, in the valleys, and
over the surface of the rivers and other bodies of water, during the
night, and most frequently the latter part of it, and is at its acme at
sunrise, or soon after, limiting vision horizontally and perpendicularly,
and dissolving away during the forenoon. It is rarely more than from two
to four hundred feet in height at its upper surface, and often much less,
and is composed of vesicular condensed vapor, sometimes sufficiently dense
to fall in mist, and is doubtless in composition substantially what the
clouds are in the other strata of the atmosphere, as observed by us, or
passed through by aeronauts. I have never seen it carried up to any
considerable height into