CHAP. I.

INTRODUCTORY.

THE ocean is the great receptacle of fishes. It has been thought, by some, that all fish are naturally of that salt element; and that they have mounted up into fresh water by some accidental migration. A few still swim up rivers to deposit their spawn; but of the great body of fishes, of which the size is enormous, and the shoals are endless, those all keep to the sea, and would quickly expire in fresh water. In that extensive and undiscovered abode, millions reside, whose manners are a secret to us, and whose very form is unknown. The curiosity of mankind, indeed, has drawn some from their depths, and his wants many more: with the figure of these at least he is acquainted; but for their pursuits, migrations, societies, antipathies, pleasures, times of gestation, and manner of bringing forth, these are all hidden in the turbulent element that protects them.

The number of fish to which we have given

1 It is believed that at great depths in the ocean, animal life ceases to exist, and that fishes are not to be found where the water is excessively deep. It has been satisfactorily proved that fishes have certain limits in high stations. Raymond ascertained that the only fishes which occur in the waters of the Pyrenees, at the height of from 1,000 to 1,162 toises, are three species of trout. Higher up, all fishes disappear. The water salamander also ceases to live at the height of 1,292 toises;-probably because the higher lakes are generally half the year covered with ice. But cold is not the sole cause, as Humboldt says, that in the equatorial regions of America, where the freezing point of water begins 1,500 toises higher than in the Pyrenees, the fishes disappear earlier in the lakes and rivers. No trouts occur in the Andes. Under the equator, from 1,800 to 1,900 toises, where most of the lakes scarcely freeze any time during the year, fishes are no longer met with, with the exception of the remarkable Peinelodes Cyclopum, which are thrown out in thousands with the clay-mud, projected from fissures of the rocks at the height of 2,500 toises. But these fishes live in the subterranean lakes.-ED.

names, and of the figure, at least, of which we know something, according to Linnæus, are above four hundred. Thus to appearance, indeed, the history of fish is tolerably copious; but when we come to examine, it will be found that of the greatest part of these we know very little. Those qualities, singularities, or advantages, that render animals worth naming, still remain to be discovered. The history of fishes, therefore, has little in it entertaining: for our philosophers hitherto, instead of studying their nature, have been employed in increasing their catalogues; and the reader, instead of observations or facts, is presented with a long list of names, that disgust him with their barren superfluity. It must displease him to see the language of science increasing, while the science itself has nothing to repay the increasing tax laid upon his memory.

Most fish offer us the same external form; sharp at either end, and swelling in the middle; by which they are enabled to traverse the fluid which they inhabit, with greater celerity and ease. That peculiar shape which Nature has granted to most fishes, we endeavour to imitate in such vessels as are designed to sail with the greatest swiftness: however, the progress of a machine moved forward in the water by human contrivance, is nothing to the rapidity of an animal destined by nature to reside there. Any of the large fish overtake a ship in full sail with great ease, play round it without effort, and outstrip it at pleasure. Every part of the body seems exerted in this despatch; the fins, the tail, and the motion of the whole back-bone, assist progression; and it is to that flexibility of body at which art cannot arrive, that fishes owe great velocity.

their

The chief instrument in a fish's motion, are the fins, which, in some fish, are much more numerous than in others. A fish completely fitted for sailing, is furnished with not less than two

2 About 1,500 species of fish are now known, and of this number about 200 are found on the coast or in the inland waters of Britain.-ED.