which it reposes, are invisible to mortal eye.

Within a few years, the progress of scientific knowledge has enabled man
to measure the depths of the ocean, which were formerly believed to be
as unfathomable as boundless in extent. From soundings which have been
taken, it is ascertained that the configuration of the earth at the
bottom of the sea, is similar to that portion which rises above the
surface, undulating, and interspersed with hills, and valleys, and
plains, and mountain ranges, and abrupt precipices. The greatest depth
of water at which soundings have been obtained, being between five and
six miles, is deeper than the altitude of the highest mountain of which
we have knowledge; and there may be cavities of far greater depth.
Geological researches prove that at an early period of the history of
the earth its surface was vastly more irregular than at the present
time. Not only the mountains on the earth were higher, but the deepest
valleys of ocean were far deeper. Disintegrations caused by exposure to
water or the atmosphere, and abrasions from causes with which we may not
be familiar, have lowered the mountain tops, and created deposits which
raise the plains and fill the deepest chasms. And here geologists find
the origin of the earliest formation of stratified rocks.

Men have striven in vain to develop the secrets which lie hidden in
the sea. Imagination has been at work for ages, and in some cases has
pictured the bottom of ocean as a sort of marine paradise, a nautical
Eden, with charming grottoes, spacious gardens, coral forests, ridges of
golden sands, and heaps of precious gems; and abounding in inhabitants
with fairy forms, angelic features, and other attributes corresponding
with the favored region in which they flourish, who sometimes rise to
the surface of ocean, and seated on the craggy rocks, sing sweet ballads
to charm away the life of the unwary mariner. Leyden, a Scottish poet,
imagines one of these charming denizens of the deep to describe, in the
following poetic language, the attractions of this submarine world:

"How sweet, when billows heave their head,
And shake their arrowy crests on high,
Serene, in Ocean's sapphire bed,
Beneath the trembling surge to lie!

"To trace with tranquil step the deep,
Where pearly drops of frozen dew,
In concave shells, unconscious sleep,
Or shine with lustre, silvery blue.

"Then shall the summer's sun f