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.

THE OCEAN.

Oh thou vast ocean! ever sounding sea!
Thou symbol of a drear immensity!

Thou thing that windest round the solid world
Like a huge animal, which, downward hurled
From the black clouds, lies weltering and alone,
Lashing and writhing till its strength be gone!
Thy voice is like the thunder, and thy sleep
Is as a giant's slumber, loud and deep.
Thou speakest in the east and in the west
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
At will, and wound its bosom as they go:
Ever the same, it hath no ebb, no flow;
But in their stated rounds the seasons come,
And pass like visions to their viewless home,
And come again, and vanish: the young Spring
Looks ever bright with leaves and blossoming;
And Winter always winds his sullen horn,
When the wild Autumn, with a look forlorn,
Dies in his stormy manhood; and the skies
Weep, and flowers sicken, when the Summer flies.

Thou only, terrible ocean, hast a power,

A will, a voice, and in thy wrathful hour,
When thou dost lift thine anger to the clouds,

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,
And lovely in repose; thy summer form
Is beautiful, and when thy silver waves
Make music in earth's dark and winding caves,
I love to wander on thy pebbled beach,

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,
While many a sparkling star, in quiet glee,
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
Between the floating ships of ice,

Those navies of the northern main;
Those arctic ventures blindly hurled,
The proofs of Nature's olden force,
Like fragments of a crystal world

Long shattered from its skiey course.
2. These are the hurricanes that fright

The middle sea with dream of wrecks,
And freeze the south winds in their flight,
And chain the Gulf Stream to their decks.
At every dragon prow and helm

There stands some viking as of yore,
Grim heroes from the boreal realm,
Where Odin rules the spectral shore.
3. Up signal there! and let us hail

Yon looming phantom as we pass;
Note all her fashion, hull and sail,
Within the compass of your glass.
See at her mast the steadfast glow

Of that one star of Odin's throne;
Up with our flag, and let us show

The constellation on our own.
And speak her well; for she might say,

If from her heart the words could thaw,
Great news from some far frozen bay,
Or the remotest Esquimaux.

4. No answer: but the sullen flow

Of ocean heaving long and vast;

An argosy of ice and snow,

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.

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3.

The floor is of sand, like the mountain-drift,

And the pearl-shells spangle the flinty snow;
From coral rocks the sea-plants lift

Their boughs, where the tides and billows flow;
The water is calm and still below,

For the winds and waves are absent there;
And the sands are bright as the stars that glow
In the motionless fields of the upper air.

There, with its waving blade of green,

The sea-flag streams through the silent water,
And the crimson leaf of the dulse is seen

To blush like a banner bathed in slaughter;
There, with a light and easy motion,

The fan-coral sweeps through the clear deep sea,
And the yellow and scarlet tufts of ocean

Are bending like corn on the upland lea;
And life in rare and beautiful forms

Is sporting amid those bowers of stone,
And is safe when the wrathful spirit of storms
Has made the top of the waves his own.

And when the ship from his fury flies

Where the myriad voices of ocean roar,
When the wind-god frowns in the murky skies,

And demons are waiting the wreck on shore,

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.

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2.

LESSON XVIII.-OCEAN WAVES.

ROLL on, thou deep and dark blue ocean-roll!
Ten thousand fleets sweep over thee in vain;
Man marks the earth with ruin-his control
Stops with the shore; upon the watery plain
The wrecks are all thy deed, nor doth remain
A shadow of man's ravage, save his own,

When, for a moment, like a drop of rain,
He sinks into thy depths with bubbling groan,
Without a grave, unknelled, uncoffined, and unknown.
And I have loved thee, ocean! and my joy

Of youthful sports was on thy breast to be
Borne, like thy bubbles, onward: from a boy
I wantoned with thy breakers-they to me
Were a delight; and if the freshening sea
Made them a terror, 'twas a pleasing fear,
For I was, as it were, a child of thee,
And trusted to thy billows far and near,
And laid my hand upon thy mane-as I do here.-BYRON.

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 "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!