by the deception, as it might be if two distant points
in space were suddenly brought into immediate proximity. Let us suppose,
for a moment, that a philosopher should lie down to sleep in some arctic
wilderness, and then be transferred by a power, such as we read of in
tales of enchantment, to a valley in a tropical country, where, on
awaking, he might find himself surrounded by birds of brilliant plumage,
and all the luxuriance of animal and vegetable forms of which Nature is
so prodigal in those regions. The most reasonable supposition, perhaps,
which he could make, if by the necromancer's art he were placed in such
a situation, would be, that he was dreaming; and if a geologist form
theories under a similar delusion, we cannot expect him to preserve more
consistency in his speculations than in the train of ideas in an
ordinary dream.

It may afford, perhaps, a lively illustration of the principle here
insisted upon, if I recall to the reader's recollection the legend of
the Seven Sleepers. The scene of that popular fable was placed in the
two centuries which elapsed between the reign of the emperor Decius and
the death of Theodosius the younger. In that interval of time (between
the years 249 and 450 of our era) the union of the Roman Empire had been
dissolved, and some of its fairest provinces overrun by the barbarians
of the north. The seat of government had passed from Rome to
Constantinople, and the throne from a pagan persecutor to a succession
of Christian and orthodox princes. The genius of the empire had been
humbled in the dust, and the altars of Diana and Hercules were on the
point of being transferred to Catholic saints and martyrs. The legend
relates, "that when Decius was still persecuting the Christians, seven
noble youths of Ephesus concealed themselves in a spacious cavern in the
side of an adjacent mountain, where they were doomed to perish by the
tyrant, who gave orders that the entrance should be firmly secured with
a pile of huge stones. They immediately fell into a deep slumber, which
was miraculously prolonged, without injuring the powers of life, during
a period of 187 years. At the end of that time the slaves of Adolius, to
whom the inheritance of the mountain had descended, removed the stones
to supply materials for some rustic edifice: the light of the sun darted
into the cavern, and the Seven Sleepers were permitted to awake. After a
slumber, as they thought, of a few hours, they were pres