5281. MIRAGE AT MONTICELLO.—
The elevation and particular situation at Monticello
afford an opportunity of seeing a phenomenon
which is rare at land, though frequent at
sea. The seamen call it looming. Philosophy
is as yet in the rear of the seamen, for so far
from having accounted for it, she has not given
it a name. Its principal effect is to make distant
objects appear larger, in opposition to the
general law of vision, by which they are diminished.
I know an instance, at Yorktown, from
whence the water prospect eastwardly is without
termination, wherein a canoe with three
men, at a great distance was taken for a ship
with its three masts. I am little acquainted
with the phenomenon as it shows itself at sea;
but at Monticello it is familiar. There is a
solitary mountain about forty miles off in the
South, whose natural shape, as presented to
view there, is a regular cone; but by the effect
of looming, it sometimes subsides almost totally
in the horizon; sometimes it rises more acute
and more elevated; sometimes it is hemispherical;
and sometimes its sides are perpendicular,
its top flat, and as broad as its base. In short,
it assumes at times the most whimsical shapes,
and all these perhaps successively in the same
morning. The Blue Ridge of mountains comes
into view, in the north-east, at about one hundred
miles distance, and approaching in a direct
line, passes by within twenty miles, and goes
off to the south-west. This phenomenon begins
to show itself on these mountains at about
fifty miles distance, and continues beyond that
as far as they are seen. I remark no particular
state, either in the weight, moisture, or heat of
the atmosphere, necessary to produce this. The
only constant circumstances are its appearance
in the morning only, and on objects at least
forty or fifty miles distant. In this latter circumstance,
if not in both, it differs from the
looming on the water. Refraction will not
account for the metamorphosis. That only
changes the proportions of length and breadth,
base and altitude, preserving the general outlines.
Thus it may make a circle appear elliptical,
raise or depress a cone, but by none of
its laws, as yet developed, will it make a circle
appear a square, or a cone a sphere.—
Notes on Virginia. Washington ed. viii, 327.
Ford ed., iii, 186.
(1782)
