4. The ocean currents are, for the most part, the result of the very great evaporation that takes place in the vast waters of the tropical regions. The immense quantity of water there carried off by evaporation disturbs the balance or poise of the seas, and to restore this balance there is a perpetual flow of water from the polar regions.

5. Now, when these streams of cold water leave the polar regions, they flow directly towards the equator. But, before travelling far southward, their course is turned aside by the daily rotation of the earth on its axis. Still, they arrive at the tropics before they have gained the same velocity of rotation as the waters of the Torrid Zone. On that account they are left behind, and flow in a direction contrary to the diurnal motion of the earth. And hence the whole surface of the ocean for thirty degrees on each side of the equator flows from east to west in a broad stream or current (the 'Equatorial Current'), three thousand miles broad.

6. Such would be the steady and constant flow of the waters of the ocean, were it not for the land. But the land breaks in on this regular westerly movement of the waters, sending some to the north and others to the south, according to the 'lay' of the land.

7. Thus it is in the case of the great equatorial current in the Atlantic. From off Cape St Roque, in South America, its principal branch takes a north-westerly course. Rushing along the coast of Brazil, it passes through the Caribbean Sea. Thence, sweeping round the Gulf of Mexico, it flows between Florida and Cuba, and so into the Atlantic. It is on entering the Atlantic that this current takes the name of the Gulf Stream, the most beautiful of all the oceanic currents.

8. In the Strait of Florida the Gulf Stream is thirty

two miles wide, and over two thousand feet deep, and it flows at the rate of four miles an hour. Its waters are of the purest ultramarine blue as far as the coast of Carolina; and so completely are they separated from the sea through which they flow, that a ship may at times be seen half in the one and half in the other.

9. As the Gulf Stream proceeds on its course, it gradually increases in width. Flowing along the coast of the United States to Newfoundland, it there turns to the east, dividing into two branches. Of these two branches, one reaches the Azores, while the other sets towards the British Islands, and away to the coasts of Norway and the Arctic Ocean. To this latter branch a peculiar interest attaches, from the fact that it wonderfully modifies the climate of all Western Europe.

10. Every west wind that blows crosses the Gulf Stream, and carries with it a portion of this heat to temper the northern winds of Europe. It is, in fact, the influence of the Gulf Stream that makes Erin the 'Emerald Isle,' and that clothes the shores of Albion in evergreen robes; while, in the same latitude, the coast of North America is fast bound in fetters of ice.

11. As a rule, the hottest water of the Gulf Stream is at or near the surface; and as the deep-sea thermometer is sent down, it shows that these waters, though still much warmer than the water on either side at the same depth, gradually become less and less warm until the bottom of the current is reached. There is everywhere a cushion of cold water between this current and the solid parts of the earth's crust.

12. This arrangement is very beautiful. For, as we have seen, it is one of the offices of the Gulf Stream to convey heat from the Gulf of Mexico, and diffuse it over Western Europe. Now, cold water parts with its

heat very slowly, or, as we say, is a good non-conductor of heat; but if the warm water of the Gulf Stream were sent across the Atlantic in contact with the solid crust of the earth, all its warmth would be lost in the first part of the way, and the mild climates of France and England would be like that of wintry, ice-bound Labrador. Maury.

EXERCISES.-1. Explain the following: (1) The extremes of heat and cold; (2) the tropical regions; (3) daily rotation of the earth on its axis; (4) diurnal motion of the earth; (5) the great equatorial current; (6) a peculiar interest attaches; (7) it modifies the climate; (8) deepsea thermometer; (9) a good non-conductor of heat.

2. Analyse and parse the following:

""Tis strange the miser should his cares employ,

To gain those riches he can ne'er enjoy.'

3. Name all the derivatives you know from the following roots: (1) Metron, a measure; (2) curro, I run; (3) curro, compounded with ob(oc-), re-, in-, sub- (suc-), dis-, con-, ex-; (4) dies, a day; (5) æquus, equal.

THE ASSAULT.

[This lesson forms the introduction to Part II. of Lord Byron's drama, The Deformed Transformed. It gives a graphic picture of the taking of Rome in 1527 by Charles of Bourbon, Constable of France. Not having been well treated in the service of France, Bourbon entered that of Charles V., Emperor of Germany; and he led a wild army against Rome, which was taken and ruthlessly plundered, but Bourbon himself fell mortally wounded while in the act of ascending a scaling ladder.]

1. 'Tis the morn, but dim and dark,
Whither flies the silent lark?
Whither shrinks the clouded sun?
Is the day indeed begun ?
Nature's eye is melancholy
O'er the city high and holy;
But without there is a din
Should arouse the saints within,
And revive the heroic ashes
Round which yellow Tiber dashes.
Oh, ye seven hills! awaken,
Ere your very base be shaken!

2. Hearken to the steady stamp—
Mars is in their every tramp!
Not a step is out of tune;

As the tides obey the moon,

On they march, though to self-slaughter,

Regular as rolling water,

Whose high waves o'ersweep the border
Of huge moles, but keep their order,
Breaking only rank by rank.

Hearken to the armour's clank!

3. Look upon the bristling wall,
Manned without an interval!
Round and round, and tier on tier,
Cannon's black mouth, shining spear,
Lit match, bell-mouthed musquetoon,
Gaping to be murderous soon.
All the warlike gear of old,
Mixed with what we now behold,
In this strife, 'twixt old and new,
Gathered like a locust's crew.

4. Near-and nearer—nearer still—
As the earthquake saps the hill-
First with trembling hollow motion,
Like a scarce awakened ocean;

Then with stronger shock and louder,
Till the rocks are crushed to powder-

5. Onward sweep the varied nations!

Famine long hath dealt their rations.
To the wall, with Hate and Hunger,
Numerous as wolves, and stronger,
On they sweep. Oh, glorious city!
Must thou be a theme for pity?
Fight like your first sire, each Roman!
Alaric was a gentle foeman,

Matched with Bourbon's black banditti.

Rouse thee, thou Eternal City!

Rouse thee! Rather give the torch
With thy own hand to thy porch,
Than behold such hosts pollute
Your worst dwelling with their foot.

6. Now they reach thee in their anger: Fire, and smoke, and fiendish clangour