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more than six grains, supported in a platinum spoon, be introduced into it by means of a piece of bent platinum wire; let the sun's rays, concentrated by means of a burning glass, be then directed upon the carbon through the glass flask. The carbon will be ignited by the solar heat, and will burn in the oxygen with great splendour.

When the combustion has ceased, and the gas contained in the flask has cooled, it will be found that the mercury in the neck of the flask will stand at exactly the same elevation as it did before the combustion. The gas contained in the flask has therefore the same volume as before, nevertheless it is easy to show that it is by no means the same gas.

In the first place, if it be weighed, it will be found to weigh 22 grains instead of 16 grains; and if the unburned residue of the carbon be weighed, its weight will be found to be 6 grains less than it was before the experiment. The inference is, that 6 grains of the carbon have combined with the 16 grains of the oxygen previously contained in the flask, but that in thus combining, the carbon has not made any change in the volume of the gas. If the gas contained in the flask be examined by the usual tests, it will immediately appear that it is no longer oxygen. No combustible will burn in it, and it will not support life by respiration. In fire, it will be found to be identical with the noxious gas called choke-damp, and to possess all the chemical characters of the gas called CARBONIC ACID.

If the same flask, similarly filled with nitrogen gas or azote, be submitted to a like experiment, the result will not be the same. The solar rays concentrated on the charcoal will still render it red hot, but it will not burn nor undergo any other change. On removing the focus of solar rays from it, it will become gradually cool, and when removed from the flask will have the same weight as when introduced into it. The azote which fills the flask will also be found to be unaltered.

It follows, therefore, that the FIRE produced when carbon burns in common air is nothing more than the heat and light developed in the formation of carbonic acid, by the combination of the carbon with the oxygen of the surrounding air, and that these substances combine in the proportion of 6 parts by weight of carbon to 16 of oxygen.

It has been already shown that hydrogen combines with oxygen in the proportion of 1 part by weight of the former to 8 of the latter to form water, and that if the combination be formed in a pure or nearly pure atmosphere of the gases it is instantaneous and accompanied by an explosion. If, however, the combination takes place, as it may, in common air, the phenomena will be very different.

If pure hydrogen, compressed in a bladder or other reservoir

be allowed to issue from a small aperture, a light applied to it will cause it to be inflamed. It burns tranquilly without explosion, producing a pale yellowish flame and very feeble light, but intense heat. This is the effect attending the gradual and continual combination of the hydrogen, as it escapes from the aperture, with the oxygen of the surrounding air. It may be asked why the hydrogen issuing from the aperture does not combine with the oxygen of the air without the application of a flame to it? And also, why being once inflamed by the application of such a body, its continued application becomes unnecessary? These questions are easily resolved. The hydrogen has an affinity or attraction for oxygen, which is not strong enough to cause their combination at common temperatures, but when the temperature of the hydrogen is greatly elevated, its attraction for the oxygen becomes so exalted, that it enters into instant and spontaneous combination with it. Now by applying the flame of a lamp or candle, or any other burning body, to the jet of hydrogen, its temperature becomes so greatly raised, and its attraction for oxygen consequently so exalted, that it enters directly into combination with the oxygen of the air which is in immediate contact with it at the moment.

But it is also asked, how the continuance of the combination and the consequent maintenance of the flame takes place the candle or lamp which produced its commencement being withdrawn? This is explained by the great quantity of heat produced by the combination of the hydrogen with the oxygen. The commencement of the combination being produced by the candle or lamp, the hydrogen and oxygen themselves in the act of combining develop an intense heat, and the succeeding portion of hydrogen gas being in contact with them becomes heated, and combines like the former with a fresh portion of oxygen. In the same manner, the heat developed by these being shared by the succeeding portion of gas, a further combination and development of heat takes place, and so on. Thus the combination being once commenced, the heat necessary for its maintenance and continuity is developed in the process itself, which accordingly goes on without the necessity of being again kindled by the application of any flame. The continuance of the combustion of carbon, whether in pure oxygen gas or in common air, is explained in the same manner.

The combustion of carbon differs from that of hydrogen in this, that the former takes place without the production of flame. The charcoal being heated to redness, and still in the solid form, enters directly into combination with the oxygen of the surrounding air, and the carbonic acid which is formed being a gas which is not luminous nor visible, the carbon disappears. But in the case of hydrogen, the heat produced by

the combustion is so intense as to render the gas itself luminous, just as intense heat will render a mass of iron red-hot or white hot. When gas becomes thus luminous it is called flame.

EVOLUTION TO THE THIRD POWER OR CUBE ROOT.

(1) Find the cube root of 729.

(2) What number multiplied twice by itself will give 493039 ? (3) Find the cube root of 929714176.

(4) Find the cube root of 2.

(5) What is the cube root of 2? (6) Find the cube root of 37.

(7) Find the cube root of 1.

SELECTIONS

FROM THE POEMS OF GRAY,

GOLDSMITH, CHATTERTON, AND BEATTIE.

THE BARD.

(Thomas Gray)

[Born, 1716; died, 1771. Poems: Ode to Eton College,' Elegy written in a Country Churchyard,' 'The Progress of Poesy,' 'The Bard,' 'Ode to Adversity,' &c.]

tis'-sue, cloth interwove with gold or

silver

warp (n.), a thread that runs lengthwise in a loom

woof (n.), threads that cross the warp ob'-se-quies, funereal solemnities

em'-bry-o, the rudiments or first parts of an animal or plant

rat'-i-fy, to confirm

round'-e-lay, an ancient ballad or poetical composition

gar-ish, gaudy, showy

sym-pho-ni-ous, sounding sweetly toge ther

phil-o-me'-la, the Latin for nightingale in-thral', to enslave

The following ode is founded on the tradition that Edward I., to complete the conquest of Wales, ordered all the bards to be destroyed.

'RUIN seize thee, ruthless king!

Confusion on thy banners wait;

Though fanned by conquest's crimson wing,
They mock the air with idle state.

Helm, nor hauberk's twisted mail,
Nor e'en thy virtues, tyrant, shall avail
To save thy secret soul from nightly fears,
From Cambria's curse, from Cambria's tears!'
Such were the sounds that o'er the crested pride
Of the first Edward scattered wild dismay,
As down the steep of Snowden's shaggy side

He wound with toilsome march his long array.
Stout Glo'ster stood aghast in speechless trance:
To arms! cried Mortimer, and couched his quivering lance.

On a rock, whose haughty brow
Frowns o'er old Conway's foaming flood,
Robed in the sable garb of wo,

With haggard eyes the poet stood

(Loose his beard and hoary hair

Streamed, like a meteor, to the troubled air);
And, with a master's hand, and prophet's fire,
Struck the deep sorrows of his lyre.

'Hark how each giant oak and desert cave
Sighs to the torrent's awful voice beneath!
O'er thee, O king! their hundred arms they wave,
Revenge on thee in hoarser murmurs breathe;
Vocal no more, since Cambria's fatal day,

To high-born Hoel's harp, or soft Llewellyn's lay.
Cold is Cadwallo's tongue,

That hushed the stormy main :
Brave Urien sleeps upon his craggy
Mountains, ye mourn in vain
Modred, whose magic song

bed :

Made huge Plinlimmon bow his cloud-topped head.
On dreary Arvon's shore they lie,

Smeared with gore, and ghastly pale:

Far, far aloof the affrighted ravens sail;
The famished eagle screams, and passes by.
Dear lost companions of my tuneful art,

Dear as the light that visits these sad eyes,
Dear as the ruddy drops that warm my heart,
Ye died amidst your dying country's cries-
No more I weep. They do not sleep.
On yonder cliffs, a grisly band,

I see them sit; they linger yet,
Avengers of their native land:

With me in dreadful harmony they join,

And weave with bloody hands the tissue of thy line.

'Weave the warp, and weave the woof,
The winding-sheet of Edward's race.
Give ample room, and verge enough
The characters of hell to trace.
Mark the year, and mark the night,

When Severn shall re-echo with affright

The shrieks of death, through Berkley's roof that ring,
Shrieks of an agonising king!

She-wolf of France, with unrelenting fangs,

That tear'st the bowels of thy mangled mate,

From thee be born, who o'er thy country hangs

The scourge of Heaven! What terrors round him wait!

Amazement in his van, with Flight combined,
And Sorrow's faded form, and Solitude behind.

"Mighty victor, mighty lord,

Low on his funeral couch he lies! No pitying heart, no eye afford

A tear to grace his obsequies.

Is the sable warrior fled?

Thy son is gone. He rests among the dead.
The swarm, that in thy noontide beam were born?
Gone to salute the rising morn.

Fair laughs the morn, and soft the zephyr blows,
While proudly riding o'er the azure realm,
In gallant trim the gilded vessel goes:

Youth on the prow, and Pleasure at the helm :
Regardless of the sweeping whirlwind's sway,
That, hushed in grim repose, expects his evening prey.
Fill high the sparkling bowl,

The rich repast prepare;

Reft of a crown, he yet may share the feast:
Close by the regal chair

Fell Thirst and Famine scowl

A baleful smile upon their baffled guest.
Heard ye the din of battle bray,

Lance to lance, and horse to horse?

Long years of havoc urge their destined course, And through the kindred squadrons mow their way. Ye towers of Julius, London's lasting shame, With many a foul and midnight murder fed, Revere his consort's faith, his father's fame, And spare the meek usurper's holy head! Above, below, the rose of snow,

Twined with her blushing foe, we spread: The bristled boar, in infant gore

Wallows beneath the thorny shade.

Now, brothers, bending o'er the accursed loom, Stamp we our vengeance deep, and ratify his doom.

'The verse adorn again

Fierce War, and faithful Love,

And Truth severe, by fairy Fiction dressed.

In buskined measures move

Pale Grief, and pleasing Pain,

With Horror, tyrant of the throbbing breast.

A voice, as of the cherub-choir,

Gales from blooming Eden bear;

And distant warblings lessen on my ear,

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