Page images
PDF
EPUB

such names.

The whole class of Medusae are

called by sailors jelly-fishes, or sea-blubber.

These animals have a very singular appearance when swimming in the water. The different species are of various forms and of all sizes, but they all seem to consist of a transparent jelly, of a symmetrical and curious form, but without limbs or members, and they move through the water by a series of alternate contractions and expansions, by means of which they make a certain degree of progress, though in the main they are drifted to and fro wherever the tides and currents bear them.

The substance of which they are composed, as has already been said, consists of a transparent jelly, but it is sometimes adorned with curious and beautiful tints of color, and certain lines are seen in some cases ramifying through it, forming a net-work of a very geometrical character, and denoting the complete organization of the mass.

Some of the species have a sort of fringe of hairs, like little snakes, which hang from the margin of the cup-shaped disc that is formed by their bodies, and float writhing and twisting in the water, as the cup, by alternate expansions and contractions, forces its way along. It is from this circumstance that they have received their name of Medusae-Medusa having been a fabled mon

ster of ancient times, whose head was adorned with snakes instead of hair.

[graphic][graphic][merged small]

Many of the medusae are phosphorescent, and these luminous species are sometimes so numerous that the whole surface of the ocean glows with them at night, as if the waves were undulations of liquid fire.

The different species vary extremely, both in form and in size. Some are so minute as not to be seen by the naked eye, in consequence of which it often happens that curious persons, seeing some evening the whole surface of the sea glowing with the light which they produce, are surprised to find

nothing visible in the water, when they draw up a bucket full of it to the deck of the ship, in order to ascertain the cause.

Others of the medusae are of great size and strength. They will seize and devour fishes of considerable magnitude, and yet their bodies contain so little substance that when drawn up upon the beach they look like a mere mass of jelly, and on being exposed for a short time to the sun and air almost entirely dry up and disappear, leaving nothing behind them but a thin filmy web, wholly shapeless and unmeaning.

For some reason or other animals of this class swarm in countless millions in all the northern seas. So dense are the schools sometimes that the whole color of the sea, for hundreds of miles, is changed by them. They furnish, of course, immense quantities of food for whales and other cetaceous animals, and also for fishes of all kinds, which in their turn give sustenance to bears, seals, walruses, and multitudes of other animals. All these animals are provided with warm coats, either of fur for the land or of blubber for the water, to enable them to endure the intense cold of the dreary region which thus furnishes them with such exhaustless supplies of food.

NEITHER DAY NGE NIGHT.

In these polar regions there is, strictly speaking, neither day nor night, but only mornings and evenings, as it were, for the sun never rises higher than a few degrees above the horizon, nor sinks more than a few degrees below. It is, therefore, lover very dark at any period of the day or of the year. On the shores of Bafin's Bay it has been found, in the experience of ships wintering there, that in mid-winter, and at the part of the day when the sun is furthest below the horizon, the twilight is so bright that the finest print can be read by it.

Of course, the brightness of this midnight twilight varies with the latitude. The further north we go, and the less the altitude which the sun attains in rising above the horizon, the less is his depression when he sinks below it. Thus, by a beautiful compensation, what would otherwise be the intolerable gloom of a so long protracted period of darkness and cold is greatly diminished.

In addition to this perpetual twilight the motions of the electric currents, and the extraordinary play of mists and vapors in the air, give rise to halos, parhelions, luminous meteors and corruscations of the aurora borealis in great abundance, by

which the aspect of the sky, during the long period of the absence of the sun, is greatly en

livened and cheered.

ICE PRODUCED UPON THE LAND.

The great means of intercommunication between the different coasts and islands of these northern seas is the ice. This ice is of two different kindsthat which is formed upon the land and that which is formed upon the sea.

Upon the land the rains and snows of a vast succession of seasons accumulate, and form beds of solid ice called glaciers, which increase until they become not unfrequently thousands of feet in thickness. These glaciers fill the valleys, and sometimes occupy immense slopes of land declining toward the sea. They are formed wherever there is a tract so situated, in respect to higher land surrounding it, that it can retain the snow that is driven into it by the winds, or that slides into it in avalanches, and also receive the water of the summer streams. The effect of time and cold is to

cement all these supplies-rain, snow, sleet and hail-into one solid mass of homogeneous ice, which, however, is nevertheless, notwithstanding its solidity, subject to a slow motion like that of lava nearly cooled, which, though men can travel over

« PreviousContinue »