e
celestial arch--which is white near midnight. Now, in the
opinion of some, it takes the color of the four elements:
the red from fire, the green from the earth, the white from
the air, and blue from the water. Aristotle, in his book
entitled _Meteors_, is of a very different opinion. He says:
'The celestial arch is a repercussion of the sun's rays in
the vapors of the clouds where they meet, as brightness
reflected from the water upon the wall returns to itself.
By its interposition it tempers the heat of the sun; by
resolving itself into rain it fertilizes the earth, and by
its splendor beautifies the heavens. It demonstrates that
the atmosphere is filled with humidity, which will disappear
forty years before the end of the world, which will be an
indication of the dryness of the elements. It announces
peace between God and man, is always opposite the sun, is
never seen at noon, because the sun is never in the north.'

"But Pliny says that after the autumnal equinox it appears
every hour. This I have extracted from the _Comments of
Landino_ on the fourth book of the _AEneid_, and I mention it
that no man may be deprived of the fruits of his labors, and
that due honors may be rendered to every one. I saw this bow
two or three times; neither am I alone in my reflections
upon this subject, for many mariners are also of my opinion.
We saw also the new moon at mid-day, as it came into
conjunction with the sun. There were seen also, every night,
vapors and burning flames flashing across the sky. A little
above, I called this region by the name of hemisphere,
which, if we would not speak improperly, cannot be so called
when comparing it with our own. It appeared to present that
form only partially, and it seemed to us speaking improperly
to call it a 'hemisphere.'

"As I have before stated, we sailed from Lisbon--which is
nearly forty degrees distant from the equinoctial line
towards the north--to this country, which is fifty degrees
on the other side of the line. The sum of these degrees is
_ninety_, and is the fourth part of the circumference of the
globe, according to the true reckoning of the ancients. It
is therefore manifest to all _that we measured the fourth
part of the earth_.[13]

"We who reside in Lisbon, nearl