and we do
not forget. So ends the astronomer's voyage to fairyland.

[Illustration]

HALOS--PARHELIA--THE SPECTRE OF THE BROCKEN, ETC

(FROM THE ATMOSPHERE.)

BY CAMILLE FLAMMARION.

[Illustration]

Treatises on meteorology have not, up to the present day, classified
with sufficient regularity the divers optical phenomena of the air.
Some of these phenomena have, however, been seen but rarely, and have
not been sufficiently studied to admit of their classification. We
have examined the common phenomenon of the rainbow and we have seen
that it is due to the refraction and reflection of light on drops of
water, and that it is seen upon the opposite side of the sky to the
sun in day-time, or the moon at night. We are now about to consider an
order of phenomena which are of rarer occurrence, but which have this
property in common with the rainbow, viz., that they take place also
upon the side of the sky opposite to the sun. These different optical
effects are classed together under the name of _anthelia_ (from
Greek, opposite to, and Greek, the sun). The optical phenomena which
occur on the same side as, or around the sun, such as halos, parhelia,
etc., will be dealt with later on.

Before coming to the anthelia, properly so called, or to the colored
rings which appear around a shadow, it is as well first to note the
effects produced on the clouds and mists that are facing the sun when
it rises or sets.

Upon high mountains, the shadow of the mountain is often seen thrown
either upon the surface of the lower mists or upon the neighboring
mountains, and projected opposite to the sun almost horizontally. I
once saw the shadow of the Righi very distinctly traced upon Mount
Pilate, which is situated to the west of the Righi, on the other side
of the Lake of Lucerne. This phenomenon occurs a few minutes after
sunrise, and the triangular form of Righi is delineated in a shape
very easy to recognize.

The shadow of Mont Blanc is discerned more easily at sunset. MM.
Bravais and Martins, in one of their scientific ascents, noticed it
under specially favorable circumstances, the shadow being thrown upon
the snow-covered mountains, and gradually rising in the atmosphere
until it reached a height of 1 deg., still remaining quite visible. The
air above the cone of the shadow was tinted with that rosy purple
which is seen, in a fine sunset, coloring the lofty peaks. "Imagine,"
says Bravais, "the other mountains also