yet undescribed by the naturalist.

It may be asked why so many creatures of different kinds congregate in
this part of the ocean? Upon what do they subsist? what food can they
find so far from land?

A ready reply to these questions may be given, by saying, that they
subsist upon each other; and this would be, to some extent, true. But
then there must be a base forming the food for all, and produced by some
process of nature. What process can be going on in the midst of the
ocean to furnish the subsistence of such myriads of large and voracious
creatures? In the waters of the great deep, apparently so pure and
clear, one would think that no growth,--either animal or vegetable,
could spring up,--that nothing could come out of nothing. For all this,
in that pure, clear water, there is a continual process of production,--
not only from the soil at the bottom of the sea, but the salt-water
itself contains the germs of material substances, that sustain life, or
become, themselves, living things, by what appears, to our ignorant
eyes, spontaneous production.

There is no spontaneity in the matter. It is simply the principle of
creation, and acting under laws and by ways that, however ill-understood
by us, have existed from the beginning of the world.

It is true that the whole extent of the great oceans are not thus
thickly peopled. Vast tracts may be traversed, where both fish and
birds of all kinds are extremely scarce; and a ship may sail for days
without seeing an individual of either kind. A hundred miles may be
passed over, and the eye may not be gratified by the sight of a living
thing,--either in the water or the air. These tracts may truly be
termed the deserts of the sea; like those of the land, apparently
uninhabited and uninhabitable.

It may be asked, Why this difference, since the sea seems all alike?
The cause lies not in a difference of depth: for the tracts that teem
with life are variable in this respect,--sometimes only a few fathoms in
profundity, and sometime unfathomable.

The true explanation must be sought for elsewhere. It will be found not
in _depth_, but in _direction_,--in the direction of the currents.

Every one knows that the great oceans are intersected here and there by
currents,--often hundreds of miles in breadth, but sometimes narrowing
to a width of as many "knots." These oceanic streams are regular,
though not regularly defined. They are not caused by mere temporary
s