always proceed in right lines, unless turned aside or stopped in their passage. The former effect always takes place when a ray passes into a medium of a different density from that which it is leaving; and this turning aside is called refraction. The atmosphere is known to have this influence on the solar rays, and thus to produce the twilight, by which we have the benefit of the sun before he rises in the morning and after he sets at night. The air has also a reflective power, by which objects are enlightened on all sides, without which their shadows would be so dark, and their enlightened sides so very bright, that we should only be able to see those parts of them which are absolutely exposed to the sun's rays, if indeed the stream of light did not render them too powerful for the optic nerve.

Lastly, we must notice its chemical properties. These consist chiefly in the power of holding water in solution, which the atmosphere possesses in a very remarkable degree, though variable in different states and circumstances, and in that strong and uniform affinity by which the different gases which form the atmosphere are held in combination. So invariable is this proportion found, that on analysing the air in different parts of the world, obtained in different states and from different altitudes, the proportion of its constituent parts has always been found the same.

The uses of the atmosphere are so great and so numerous, that it is absolutely necessary, not only to the comfort and convenience of the human race, but even to the existence of all animal and vegetable life, and to the very constitution of all kinds of matter, without which they would not be what they are; for, by insinuating itself into all the vacuities of bodies, it becomes the great spring of all the mutations which are taking place among bodies. Without it we should have no sound, no light—at least, no vision-no vegetables, no fire, no pleasant conversation, no mortal life. The winds would cease to blow-the ocean would no longer roll-motion among bodies at small distances would stop-the pulse of life would no longer beat, but stagnation would ensue, and “universal darkness cover all."

Now had the son of Jove,* mature, attained

The joyful prime, when youth, elate and gay, Steps into life; and follows, unrestrained,

Where passion leads, or prudence points the way.

* Hercules was fabled to be the son of Jove.

In the pure mind, at those ambiguous years,

Or vice, rank weed, first strikes her poisonous root, Or haply virtue's opening bud appears

By just degree, fair bloom of fairest fruit;

For if on youth's untainted thought imprest,

The generous purpose still shall warm the manly breast.

As on a day, reflecting on his age

For highest deeds now ripe, Alcides* sought Retirement, nurse of contemplation sage—

Step following step, and thought succeeding thought— Musing, with steady path the youth pursued His walk, and, lost in meditation, strayed Far in a lonely vale, with solitude

Conversing while intent his mind surveyed The dubious path of life, before him lay,

Here, Virtue's rough ascent-there, Pleasure's flowery way.

Much did the view divide his wavering mind

Now glowed his breast with generous thirst of fame;
Now love of ease to softer thoughts inclined

His yielding soul, and quenched the rising flame-
When, lo! far off, two female forms he spies;
Direct to him their steps they seem to bear;
Both large and tall, exceeding human size ;

Both, far exceeding human beauty, fair.
Graceful, yet each with different grace, they move;
This, striking sacred awe-that, softer winning love.

The first in native dignity surpassed;

Artless and unadorned, she pleased the more;
Health o'er her looks a genuine lustre cast;

A vest more white than new-fall'n snow she wore.
August she stepped, yet modest was her air;
Serene her eye, yet darting heavenly fire.

* Another name for Hercules, meaning "grandson of Alceus."

Still she drew near and nearer, still more fair,
More mild appeared; yet such as might inspire
Pleasure corrected with an awful fear-

Majestically sweet, and amiably severe.

The other dame seemed even of fairer hue,
But bold her mien; unguarded roved her eye;
And her flushed cheeks confessed at nearer view
The borrowed blushes of an artful dye.
All soft and delicate, with airy swim,

Lightly she danced along; her robe betrayed,
Through the clear texture, every tender limb,
Heightening the charms it only seemed to shade;

And as it flowed adown, so loose and thin,

Her stature showed more tall, more snowy-white her skin.

"Dear Hercules" (said she), "whence this delay? Dear youth, what doubts can thus distract thy mind? Securely follow where I lead the way,

And range through wilds of pleasure unconfined; With me retire from noise, and pain, and care, Embathed in bliss, and wrapt in endless ease : Rough is the road to fame, through blood and war; Smooth is my way, and all my paths are peace. With me retire, from toils and perils free:

Leave honour to the wretch-pleasures were made for thee."

By this arrived the fair majestic maid;

She all the while, with the same modest pace, Composed, advanced-" Know, Hercules," she said With manly tone, "thy birth of heavenly race. Thy tender age, that loved instruction's voice, Promised thee generous, patient, brave, and wise, When manhood should confirm thy glorious choice; Now expectation waits to see thee rise.

Rise, youth! exalt thyself and me! approve

Thy high descent from Heaven, and dare be worthy Jove!

"But what truth prompts, my tongue shall not disguise :
The steep ascent must be with toil subdued;
Watchings and cares must win the lofty prize
Proposed by Heaven-true bliss and real good.
Honour rewards the brave and bold alone;

She spurns the timorous, indolent, and base :
Danger and toil stand stern before her throne,
And guard (so Jove commands) the sacred place;
Who seeks her must the mighty cost sustain,
And pay the price of fame—labour and care and pain."
"Hear'st thou what monsters then thou must engage;
What danger, gentle youth, she bids thee prove ?”—
Abrupt says Sloth, "Ill fit thy tender age

Tumult and wars—fit age for joy and love.
Turn, gentle youth, to me, to love and joy;
To these I lead: no monsters here shall stay
Thine easy course, no cares thy peace annoy:
I lead to bliss a nearer, smoother way.
Short is my way; fair, easy, smooth, and plain :
Turn, gentle youth! with me eternal pleasures reign."

"Vast happiness enjoy thy gay allies!

A youth of follies, an old age of cares;

Young, yet enervate; old, yet never wise:

Vice wastes their vigour, and their mind impairs.

Vain, idle, delicate, in thoughtless ease,

Reserving woes for age, their prime they spend;

All wretched, hopeless, in the evil days,

With sorrow to the verge of life they tend.

Grieved with the present, of the past ashamed,

They live, and are despised: they die, nor more are named.

"But with the gods, and godlike men, I dwell :
Me, his supreme delight, the Almighty Sire
Regards well pleased: whatever works excel,
All, or divine or human, I inspire.