opening some of the most interesting departments in natural history. But it is only when we unite, in our contemplation, these various aspects, that we begin to have any adequate idea of the real interest and importance of this, the grandest division of our globe. 2. The first impression made by a view of the ocean is doubtless that of vastness, illimitable-inappreciable; while the thoughts which its mighty waters teach are those of "Eternity, Eternity, and Power." Such thoughts are forcibly expressed in the following lines addressed to 3. 5. 6. THE OCEAN. Oh thou vast ocean! ever sounding sea! Thou thing that windest round the solid world At once, and on thy heavily-laden breast Fleets come and go, and things that have no life Or motion, yet are moved and met in strife. The earth hath naught of this: no chance nor change Ruffles its surface, and no spirits dare Give answer to the tempest-waken air; But o'er its wastes the weakly tenants range Thou only, terrible ocean, hast a power, A will, a voice, and in thy wrathful hour, A fearful and magnificent beauty shrouds Thy broad green forehead. If thy waves be driven Backward and forward by the shifting wind, How quickly dost thou thy great strength unbind, And stretch thine arms, and war at once with Heaven! Thou trackless and immeasurable main ! On thee no record ever lived again To meet the hand that writ it: line nor lead Hath ever fathomed thy profoundest deeps, Where haply the huge monster swells and sleeps, King of his watery limit, who, 'tis said, Can move the mighty ocean into storm Oh, wonderful thou art, great element, And fearful in thy spleeny humors bent, Marking the sunlight at the evening hour, And hearken to the thoughts thy waters teach "Eternity, Eternity, and Power."-BRYAN W. PROCTOR. LESSON XV. THE OCEAN: ITS PHYSICAL ASPECTS. 1. THE bed of the ocean, like dry land, is diversified by plains and mountains, table-lands and valleys, sometimes barren, sometimes covered with marine vegetation, and teeming with life. Its plateaus and depressions have been ascertained by the sounding-line, and are mapped out in profile as a part of our geographical knowledge. Its average depth is believed to be about equal to the height of the land, the lowest valleys of the ocean's bed corresponding with the summits of the loftiest mountains. 2. The ocean is continually receiving the spoils of the land, washed down by numerous rivers, and deposited as sand and mud, or held in solution in its waters. These causes tend to diminish its depth and increase its superficial extent. There are, however, causes in operation which counteract these agencies. It is clearly shown by geologists that processes of elevation and subsidence are continually taking place in different parts of the globe. 3. The waters of the ocean contain about three and a half per cent. of saline matter; but, owing to the melting of snow and ice in the polar regions, and the volumes of fresh water poured in by rivers, the degree of saltness diminishes toward the poles, and also near the shores. The temperature of the ocean, though varying in different latitudes, is more uniform than that of the land; its color, generally of a deep bluishgreen, is varied in particular localities by the myriads of animalcules and vegetable substances which float on its surface, and also, in shallow places, by the color of the bed on which it rests. In some parts of the tropical seas the waters are remarkably clear, like an immense vase of crystal; and one may look downward unmeasured fathoms beneath the vessel's keel, but still find no boundary: the sight is lost in one uniform transparent blueness. The calm "midnight ocean" of the tropics has been beautifully described in the following lines: 4. It is the midnight hour-the beauteous sea, Calm as the cloudless heaven, the heaven discloses, Far down within the watery sky reposes. As if the ocean's heart were stirr'd With inward life, a sound is heard, Like that of dreamer murmuring in his sleep; 'Tis partly the billow, and partly the air That lies like a garment floating fair Above the happy deep.-JOHN WILSON. LESSON XVI.-SHIP AMONG THE ICEBERGS. 1. A FEARLESs shape of brave device, Our vessel drives through mist and rain Those navies of the northern main; Long shattered from its skiey course. The middle sea with dream of wrecks, There stands some viking as of yore, Yon looming phantom as we pass; Of that one star of Odin's throne; The constellation on our own. If from her heart the words could thaw, 4. No answer: but the sullen flow An Of ocean heaving long and vast; The voiceless North swings proudly past. LESSON XVII.-THE DEPTHS OF OCEAN. DRUMMOND. 1. NOTHING can be more beautiful than a view of the bottom of the ocean during a calm, even round our own shores, but particularly in tropical climates, especially when it consists alternately of beds of sand and masses of rock. The water is frequently so clear and undisturbed that, at great depths, the minutest objects are visible; groves of coral are seen expanding their variously-colored clumps, some rigid and immovable, and others waving gracefully their flexile branches. Shells of every form and hue glide slowly along the stones, or cling to the coral boughs like fruit; crabs and other marine animals pursue their prey in the crannies of the rocks, and sea-plants spread their limber leaves in gay and gaudy irregularity, while the most beautiful fishes are on every side sporting around. 2. 3. 4. The floor is of sand, like the mountain-drift, And the pearl-shells spangle the flinty snow; Their boughs, where the tides and billows flow; For the winds and waves are absent there; There, with its waving blade of green, The sea-flag streams through the silent water, To blush like a banner bathed in slaughter; The fan-coral sweeps through the clear deep sea, Are bending like corn on the upland lea; Is sporting amid those bowers of stone, Where the myriad voices of ocean roar, Then far below in the peaceful sea The purple mullet and gold-fish rove, Where the waters murmur tranquilly Through the bending twigs of the coral grove.—PERCIVAL. 5. The allusion to the "peaceful sea," below the reach of the storms which agitate the surface, has reference to the well-known fact that the effects of the strongest gale do not extend below the depth of two hundred feet: were it not so, the water would be turbid, and shell-fish would be destroyed. 2. LESSON XVIII.-OCEAN WAVES. ROLL on, thou deep and dark blue ocean-roll! When, for a moment, like a drop of rain, Of youthful sports was on thy breast to be 3. The three great movements of the ocean are waves, caused by the winds, tides, caused by the attraction of the sun and moon, and currents, caused by the earth's rotatory motion and the unequal heating of the waters. 4. There is a kind of wave or undulation called a ground swell, occasioned by the long continuance of a heavy gale. This undulation is rapidly transmitted through the ocean to places far beyond the direct influence of the gale that caused it, and often it continues to heave the smooth and glassy surface of the sea long after the wind and surface waves have subsided. 5. The force of waves in severe gales is tremendous. Mr. Stephenson has estimated the force of waves which were twenty feet high as being three tons to each square foot against perpendicular masonry. Waves vary in magnitude, from a mere ripple to enormous billows, but their height in storms is from ten to twenty-two feet. From the bottom of the hollow, or "trough of the sea," the height will be double that of the wave, or from twenty to forty-four feet. The distance between one "storm wave" and another is about five hundred and sixty feet, and the velocity of the waves about thirty-two miles an hour. 6. There is no more magnificent sight than the roll of the breakers as they dash upon some rock-bound coast. The 66 roar of the surf" after a storm is often tremendous, and may be heard at the distance of many miles. The spray is sometimes thrown as high as one hundred and fifty feet; and light-houses more than a hundred feet in height are often literally buried in foam and spray, even in those ground swells where there is no wind. 7. But when an ocean wave has exhausted its force, and breaks in a gentle ripple on the shore, nothing can be more peacefully beautiful, and no music falls with sweeter cadence on the ear. How different the picture from Byron, which we have placed at the head of this lesson, from the one with which we close! |