set, and actually sunk far below
the line of direct vision.

The _Fata Morgana_ are further illustrations of this optic delusion.
This phenomenon is seen at the Pharo of Messina, in Sicily, under
certain circumstances. The spectator must stand with his back to the
east, on an elevated place behind the city, commanding a view of the
bay, and having the mountains, like a wall, opposite to him, to darken
the back ground of the picture; no wind must be abroad to ruffle the
surface of the sea; and the waters must be pressed up by currents, as
they sometimes are, to a considerable height in the middle of the
strait, and present a slight convex surface. When all these
circumstances occur, as soon as the sun rises over the heights of the
Calabrian shore, and makes an angle of 45 degrees with the horizon, all
the objects on the shore at Reggio are transferred to the middle of the
strait, and seen distinctly on the surface of the water, forming an
immoveable landscape of rocks, trees, and houses, and a moveable one of
men, horses, and cattle; these are formed into a thousand separate
compartments, presenting most beautiful and ever varying pictures of
animate and inanimate nature, on the swelling surface of the water,
broken by the currents, present separate plates of convex mirrors to
reflect them; they then as suddenly disappear, as the broad aquatic
mirror of the current passes on.

Sometimes the atmosphere is so dense that the objects are seen, like
Captain Scoresby's ship, snatched up into the regions of the air, thirty
or forty feet above the level of the sea; and in cloudy weather, nearer
to the surface, bordered with vivid prismatic colours. Sometimes
colonades of temples and churches, with cross-crowned spires, are all
represented as floating on the sea, and by a sudden change of
representation, the pillars are curved into arcades, and the crosses are
bent into crescents, and all the edifices of the floating city undergo
the most extraordinary and fantastic mutations. All these images are so
distinct, and produce objects seemingly as palpable as they are visible,
as sensible to touch as to sight, that the people of the country are
firmly persuaded of their reality. They consider the edifices as the
enchanted palaces of the fairy Morgana, and the moving objects as living
things which inhabit them. Whenever the optic phenomenon occurs, they
meet together in crowds, with an intense curiosity, mixed with awe and
apprehens