Recollections of Mexico, Chapters I-II [pp. 16-36]

RECOLLECTIONS OF MEXICO.
"What else can it be, Sefior?" rejoined the Padre, there is
not a drop of water on the whole plain, as well I ought to know."
" Well," replied the Doctor, "if that lake is a fiction there is
some foundation for enchantment."
It certainly looked too real for one's mind to realize, while
gazing upon it, that it had no actual existence. And long the
party lingered admiring the beautiful, but fictitious oasis of the
arid plain.
One of the horses having been carelessly tied below, broke
loose, and started off in the direction of the supposed lake.
"Look," cried the Doctor, "egad the horse seems to be laboring under the delusion as well as ourselves: he is evidently going
to slake his thirst. Ioulnt," said he to one of the men, " and
catch him, and be sure you water him in the lake before you
bring him back."
I was surprised at this singular phenomenon presenting itself
from so elevated a point, for it rarely appears but when the eye
is on a level, or nearly so, with the plain. But a closer examination of the locality revealed the fact of a depression of the land
where the rock stood which must have brought its top on a level
with the plain.*
The looming of ships at sea, or of distant shores is a phenomenon produced by similar atmospheric causes. In 1822, Capt. Scoresby saw by its
inverted image in the air, the ship "Fame," which afterwards proved to be
at the moment seventeen miles beyond the horizontal range of vision.
Doctor Vance in 1806, saw from Ramsgate, at which place only the tops of
the towers are visible, the whole of Dover Castle, appear as if placed bodily
on the side of a hill. On Lake Geneva a boat has been doubled and placed
some distance apart.
The Fats Morgana, so called by the natives, is an illusion of a very
singular nature, frequently seen on the Calabrian shore. On the Sicilian
shore opposite, beneath the dark back-ground of Messina, are seen refracted
and reflected-inverted images are usually the result of the latter-on the
water, gigantic figures of men and horses moving over the picture, as
figures in miniature are seen flitting across the Camera Obscura.
The number and variety presenting themselves of these ill usive but inter esting pictures, are far too great for the space these pages afford. There is
one how.ever, I will not pass over, inasmuch as it is connected with interest ing historical events.
A band of Highlanders were seen drilling on the inaccessible slope of a
hill in the memorable year 1745, in Scotland. They were so plainly visible
that the color of their tartans were distinguished. The superstitious coun try people looked upon it as a supernatural forewarning of war, which was
verified by the breaking out of the rebellion shortly after. But it was sub sequently discovered that the clan whose reflected images are recognised
on the inaccessible hill side, was at that precise time actually drilling in a
lonely glen some twenty miles off. How many presentiments which are
deemed the result of preternatural causes could be accounted for by a
knowledge of the operation of natural laws!
The "Mirage" is owing-as well as similar optical illusions-to the
unequal density, refracting and reflecting powers of adjacent strata of air,
usually close to the land or sea. This inequality is produced by the differ ence of temperature between the air and land, or water. The intense heat
of the sand on arid plains under the tropics greatly rarities the air; and rays
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