rother's rays;
Nor fleecy clouds float lightly through the sky."

The brightness of the stars and the clear appearance of the moon show the
absence of condensation and the _dissolution_ of the fleecy clouds at the
close of the day is, as we have seen, always a fair-weather indication.

There is much true philosophy in the allusions of Virgil to the moon.
Thus--

"When Luna first her scatter'd fires recalls,
If with _blunt horns_ she holds the _dusky_ air,
Seamen and swains predict th' abundant shower."

The horns, or angles of the moon will, of course, appear distinct and
sharp or indistinct and blunt, in proportion to the amount of
condensation in the atmosphere which impedes the passage of the light. For
the same reason, when the moon is new, her entire disk is visible when the
atmosphere is very clear, by reason, as is supposed, of light reflected
from the earth to the moon and back to us. This double reflection can only
take place when the atmosphere is very clear. Hence, Virgil alludes to it,
and correctly, as an indication of continued fair weather:

"If (mark the ominous hour!)
The clear fourth night her lucid disk define,
That day, and all that thence successive spring,
E'en to the finished month, are calm and dry."

Probably Virgil alluded to a month of the summer trade-wind drouth which
reaches up on Southern Italy. But that appearance of the moon is
occasionally seen here, and the indication is, in degree, philosophically
true.

It is somewhat more difficult to determine what will be the result of the
condensation seen at the west in the morning, and which is not so far
east, or of such a character, as to reflect the rays of the sun; for,
although always suspicious, it is sometimes of a foggy character, and
disappears between eight and nine o'clock. If it increases in density
after ten o'clock, or is of a dense cirro-stratus character, rain may
generally be expected. If of a decided _cirro-cumulus_ character, it is
certain to disappear. Cirro-cumulus is seen in small patches, with small,
distinct, and rounded masses, in summer, in the morning, and sometime,
during the day, after high fog has disappeared, and at other times, and is
always, when of that _distinct_ character, a fair weather indication. I
have seen it thus when the wind was blowing from the N. E., and the scud
running toward a storm passing near, but to the south of us, when those
who relied upon the exist