52 
THE PHYSICAL GEOGRAPHY OF THE SEA. 
taken in the cold water of that coast, they have a dehcious flavor 
and are highly esteemed ; but when taken 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 90°. 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 cool 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 Ghili, Peru, and Columbia, and reaches the Gallipagos Islands 
under the line. Throughout this whole distance, the world does 
not aflbrd 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 coloring with the birds, and plants, and insects of 
the tropics, are held in no esteem as an article of food. I have 
known sailors, even after long voyages, 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 seem to suggest it as a point 
of the inquiry to be made, 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 high- 
ways through which migratory fishes travel from one region to 
another. 
Navigators have often met with vast numbers of young sea- 
nettles (medusae) drifting along with the Gulf Stream. They are 
known to constitute the principal food for the whale ; but whither 
bound by this route has caused much curious speculation, for it 
is well known that the habits of the right whale are averse to the 
warm waters of this stream. An intelligent sea-captain informs 
me that, two or three years ago, in the Gulf Stream on the coast 
of Florida, he fell in with such a " school of young sea-nettles as 
had never before been heard of." The sea was covered with them 
for many leagues. He likened them, in appearance on the water, 
to acorns floating on a stream ; but they were so thick as to com- 
pletely cover the sea. He w^as bound to England, and was five 
or six days in sailing through them. In about sixty days after- 
ward, on his return, he fell in with the same school off" the West- 
era Islands, and here he was three or four days in passing them 
