manner, but as
regular an effect, and as easy to be accounted for, as the reflection of
a face in a looking glass.

This constitution of the atmosphere, and its capability of dilating
objects, and altering their position by reflection and refraction, will
easily account for many phenomena which have been considered miraculous
and preternatural in early ages, by the ignorant; and in our own, by the
weak and superstitious. Such was probably the origin of the crosses seen
by Constantine and Constantius in the first ages of Christianity, and
such was that of the cross which appeared in the sky in France, to which
so many bore attestation. A large cross of wood, painted red, had been
erected beside the church, as a part of the ceremony they were
performing. In the winter, when the air is most frequently condensed by
cold, and its different strata of various degrees of tenacity, on a
clear evening after rain, when particles of humidity, still floating in
the air gives it greater power of reflection and refraction, when the
sun was setting, and his horizontal beams found most favourable to
produce meteoric phenomena, the spectrum of this wooden cross was cast
on the concave surface of some atmospheric mirror, and so reflected
back to the eyes of the spectators from an opposite place, retaining
exactly the same shape and proportions, but dilated in size, and changed
in position; and it was moreover tinged with red, the very colour of the
object of which it was the reflected image. This delusive appearance
continued till the sun was so far sunk below the horizon, as to afford
no more light to illumine the object, and the image ceased when the rays
were no longer distinctly reflected.

CHAPTER XVII.

ELUCIDATION OF SOME ANCIENT PRODIGIES.

Many of the prodigies recorded by the ancients, admit of a natural
explanation; and an attentive examination will show that a small number
of causes, which may be discerned and developed, will serve for the
explanation of nearly the whole of them. There are two reasons for our
believing accounts of prodigies:--

1. The number and agreement of these accounts, and the confidence to
which the observers and witnesses are entitled.

2. The possibility of dissipating what is wonderful, by ascertaining any
one of the principal causes which might have given to a natural fact a
tinge of the marvellous.

Now, as regards the first reason, the ancients have recorded various
occurrences: f