of this stream upon climate that makes Erin the
"Emerald Isle of the Sea," that clothes the
shores of Albion in evergreen robes, while in the
same latitude on the American side the coasts of
Labrador are fast bound in fetters of ice. In
1831, the harbour of St. John's, Newfoundland,
was closed with ice as late as the month of
June; yet who ever heard of the port of Liverpool,
though two degrees further north, being
closed with ice, even in the dead of winter?
Scott, in one his novels, tells us that the ponds
in the Orkneys are not frozen in winter. The
people there owe their soft climate to this grand
heating apparatus, and to the latent heat of the
vapours from it, which is liberated during their
precipitation upon the regions round about.
Driftwood from the West Indies is occasionally
cast upon the islands of the North Sea and
Northern Ocean by the Gulf Stream. A few
years ago, great numbers of bonita and albercore
(tropical fish), following the Gulf Stream,
entered the English Channel, and alarmed the
fishermen of Cornwall and Devon by the havoc
which they made among the pilchards.

As the Gulf Stream is a hot sea-river
constantly running out in one direction across the
surface of the Atlantic, the water so discharged
is replaced by cold submarine sea-rivers from
sundry quarters. At the very bottom of the
Gulf Stream, when its surface temperature was
eighty degrees, the deep-sea thermometer of the
Coast Survey has recorded a temperature as low
as thirty-five degrees of Fahrenheit. These cold
waters doubtless come down from the north to
replace the warm water sent through the Gulf
Stream to moderate the cold of Spitzbergen.
Perhaps the best indication as to these cold
currents may be derived from the fish of the
sea. The whales, by avoiding its warm waters,
pointed out to the fishermen the existence of
the Gulf Stream. Not less than six or eight
thousand vessels, of all sizes and flags, are
engaged in fisheries; but of all the industrial
pursuits of the sea, the whale fishery is the most
valuable. Wherefore, in treating of the physical
geography of the sea, Captain Maury rightly
judged that a map for the whales would be
useful; it has so proved itself. The sperm
whale is a warm-water fish. The right whale
delights in cold water. An immense number
of log-books of whalers have been inspected,
with the view of detecting the parts of the
ocean in which the whales are to be found at
the different seasons of the year. In the course
of these investigations, the discovery was made
that the torrid zone is, to the right whale, as a
sea of fire, through which he cannot pass; that
the right whale of the northern hemisphere and
that of the southern are two different animals;
and that the sperm whale has never been known
to double the Cape of Good Hope—he doubles
Cape Horn.

It seems to be a physical law that cold water
fish are more edible than those of warm water.
Bearing this fact in mind as we study Captain
Maury's plate of the movements of the sea as
indicated by the thermometer, we see at a glance
the places which are most favoured with good
fish markets. Both shores of the North
America, the east coast of China, with the west
coasts of Europe and South America, are all
washed by cold waters, and therefore we may
infer that their markets abound with the most
excellent fish. The fisheries of Newfoundland
and New England, over which nations have
wrangled for centuries, are in the cold water
from Davis's Strait. The fisheries of Japan
and Eastern China, which almost, if not quite,
rival these, are situated also in the cold water.
Neither India, nor the east coasts of Africa and
South America, where the warm waters are, are
celebrated for their fish. The temperature of
the Mediterranean is four or five degrees above
the ocean temperature of the same latitude, and
the fish there are, for the most part, very
indifferent. On the other hand, the temperature
along the American coast is several degrees
below that of the ocean, and from Maine to Florida
tables are supplied with the most excellent of
fish. The " sheep's-head" of this cold current,
so much esteemed in Virginia and the Carolinas,
loses its flavour and is held in no esteem when
taken on the warm coral banks of the
Bahamas.

The same is the case with other fish: when
taken in the cold water of the coast, they have
a delicious flavour; but when caught in the
warm water on the other edge of the Gulf
Stream, though but a few miles distant, their
flesh is soft and unfit for the table. The
temperature of the water at the Balize reaches
ninety degrees. The fish taken there are not to
be compared with those of the same latitude in
this cold stream. New Orleans, therefore,
resorts to the cold waters on the Florida coasts for
her choicest fish. The same is the case in the
Pacific. A current of cold water from the south
sweeps the shores of Chili, Peru, and Columbia,
and reaches the Gallipagos Islands under the
equator. Throughout this whole distance, the
world does not afford a more abundant or
excellent supply of fish. Yet out in the Pacific,
at the Society Islands, where coral abounds,
and the water preserves a higher temperature,
the fish, though they vie in gorgeousness of
colouring with the birds and plants and insects
of the tropics, are held in no esteem as an
article of food. Sailors, even after long
voyages, have been known still to prefer their salt
beef and pork to a mess of fish taken there.
The few facts which we have bearing upon this
subject lead to the inquiry whether the habitat
of certain fish does not indicate the temperature
of the water; and whether these cold and
warm currents of the ocean do not constitute
the great highways through which migratory
fishes travel from one region to another. Why
should not fish be as much the creatures of
climate as plants, or as birds and other animals
of sea, land, and air? Indeed, we know that
some kinds of fish are found only in certain
climates; i.e. they live where the temperature
of the water ranges between certain degrees.

Midway the Atlantic, in the triangular space