at the distance of thirty miles, to which, directed by the blink, we
made way in the _Baffin_, through the channels of water represented in
the sky by bluish-grey streaks. The field we found to be a sheet of ice
150 miles in circumference!"

Another very singular appearance observed occasionally in foggy weather
is a series of bright circles, or coronae, surrounding the heads or
persons of individuals in certain positions. We have, while standing at
the mast-head of a vessel in Hudson's Straits, observed our own shadow
thrown on the sea with a bright halo round it. The day was bright and
hazy at the time. Referring to a particular case of this kind, Scoresby
says:

"During the month of July 1820, the weather being often foggy, with a
bright sun sometimes shining at the height of the day, some
extraordinary coronae were observed from the mast-head. These occurred
opposite to the sun, the centre of all the circles being in a line drawn
from the sun through the eye of the observer. On one occasion four
coloured luminous circles were observed. The exterior one might be
twenty degrees in diameter. It exhibited all the colours of the
spectrum. The next, a little within it, was of a whitish-grey colour;
the third was only four or five degrees in diameter, and though it
exhibited the colours of the spectrum, these colours were not very
brilliant. The fourth was extremely beautiful and brilliant. The
interior colour was yellow, then orange, red, violet, etcetera. The
colours of the whole three coronae were, I think, in the same order, but
of this I am not very certain. Indeed, on reflection, I suspect that
the second circle must have been in the reverse order of the first; the
first and the fourth being the same. The third was not coloured. In
the midst of these beautiful coronae I observed my own shadow, the head
surrounded by a glory. All the coronae were evidently produced by the
fog; my shadow was impressed on the surface of the sea."

The cause of these phenomena is "the reflection of the sun's rays,
decomposed by different refractions in minute globules of water, of
which the mist, wherein the coronae occur, in a great measure appears to
consist."

Mock suns, or _parhelia_, are common appearances in northern skies.
Sometimes two of these mock suns are seen, one on each side of their
great original, glowing so brightly that either of them, if we could
suppose it to have shone in the sky alone, would ha