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George. In preparing for this lesson, I learned that one cubic inch of water will form about a cubic foot of steam, which will be condensed into a cubic inch of water again when cooled below the boiling-point. 5. Mr. M. You have learned in that fact the great principle on which the steam-engine acts. The instrument represented in the figure gives a clear idea of the elementary parts of what is called the low-pressure steam-engine.* It consists of a cylindrical glass tube, B, terminating in a bulb, A. In the tube a piston moves up and down, air-tight, and a little water having been placed in the bulb, it is brought to the boilingpoint by the application of a lamp. As the steam forms, it presses the piston upward by reason of its elastic force; but on dipping the bulb into cold water, the steam condenses, and produces a partial vacuum, and the piston is then driven downward by the pressure of the external air.

A

B

Fig. 34.

6. John. And if the rod attached to the piston were made to turn a crank, or work a lever, it would very well illustrate the working of a steam-engine.

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Mr. M. Can George now tell in what respect the highpressure steam-engine differs from the low-pressure?

George. In the high-pressure engine, the steam, being admitted first on one side of the piston and then on the other, is pushed out against the atmosphere; but in the low-pressure, a partial vacuum is produced alternately on each side of the piston by allowing the steam to escape into a fountain of cold water, which condenses it.

7. Mr. M. I have here a very interesting description of the steam-engine, and of its wonderful power and multiplied uses, by Dr. Arnott, and I will read the closing part of it to you. In the view here taken of it, you see the steam-engine is not only a wonderful instrument in itself, but one of the most effective instruments of human progress and civilization ever invented.

8. "It regulates with perfect accuracy and uniformity the number of its strokes in a given time, counting or recording them, moreover, to tell how much work it has done, as a clock records the beats of its pendulum; it regulates the quantity of steam admitted to work, the briskness of the fire, the supply of water to the boiler, the supply of coals to the fire; it opens and shuts its valves with absolute precision as to time and manner; it oils its joints; it takes out any air which may accidentally enter into parts which should be vacuous; and when any thing goes wrong which it can not of itself rectify, it warns its attendants by ringing a bell.

9. "Yet with all these talents and qualities, and even when exerting the power of six hundred horses, it is obedient to the hand of a child. Its aliment is coal, wood, charcoal, or other combustibles; it consumes none while idle; it never tires, and wants no sleep; it is not subject to malady when originally well made, and only refuses to work when worn out with age; it is equally active in all climates, and will do work of any kind; it is a water-pumper, a miner, a sailor, a cotton-spinner, a weaver, a blacksmith, a miller, etc., etc.; and a small engine, in the character of a steam pony, may be seen dragging after it on a rail-road a hundred tons of merchandise, or a regiment of soldiers, with greater speed than that of our fleetest coaches. It is the king of machines, and a permanent realization of the genii of Eastern fable, whose supernatural powers were occasionally at the command of man."

10. Frank. Dr. Arnott speaks of a steam pony which is used on a rail-road. This must be the very pony which gave the poet Saxe such a pleasant "ride on the rail,'

"Singing through the forests,

Rattling over ridges,

Shooting under arches,

Rumbling over bridges;

Whizzing through the mountains,

Buzzing o'er the vale,

Bless me! this is pleasant,

Riding on the rail!"

11. Mr. M. It would have been fortunate if poets had written more on scientific and philosophical subjects, as the lan

guage of poetry is so well calculated to impress truths on the mind. In addition to the extract from Dr. Arnott, I have one from Lord Jeffrey on the same subject, the steam-engine, which I will read to you.

12. The Steam-engine.-"It has become a thing stupendous alike for its force' and its flexibility'; for the prodigious power which it can exert', and the ease, precision, and ductility with which it can be varied, distributed, and applied. The trunk of an elephant, that can pick up a pin' or rend an oak, is as nothing to it. It can engrave a seal', and crush masses of obdurate metal before it'; draw out, without breaking, a thread as fine as gossamer', and lift up a ship of war like a bauble in the air'. It can embroider muslin' and forge anchors'; cut steel into ribbons', and impel loaded vessels against the fury of the winds and waves'.

But I perceive, George, that you also have something which you wish to read. If it has any connection with this subject, we will hear it if you please, and let it conclude this lesson. George. It is a few verses from a little poem entitled

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THE SONG OF STEAM, by G. W. CUTLER.

Harness me down with your iron bands,

Be sure of your curb and rein,

For I scorn the power of your puny hands
As the tempest scorns a chain.

How I laughed, as I lay concealed from sight
For many a countless hour,

At the childish boast of human might,

And the pride of human power.

Ha ha ha! they found me at last,

They invited me forth at length,

And I rushed to my throne with a thunder-blast,

And laughed in my iron strength.

Oh then ye saw a wondus change
On earth and ocean wide,

Where now my fiery armies range,
Nor wait for wind nor tide.

Hurra! hurra! the waters o'er

The mountain's steep decline;
Time, space, have yielded to my power,
The world! the world is mine!
The rivers the sun hath earliest bless'd,
And those where his beams decline,
The giant streams of the queenly west,
And the orient floods divine.

I blow the bellows, I forge the steel,
In all the shops of trade;

I hammer the ore, and turn the wheel
Where my arms of strength are made;
I manage the furnace, the mill, the mint,
I carry, I spin, I weave;

And all my doings I put in print

On every Saturday eve.

I've no muscle to weary, no breast to decay,
No bones to be laid on the shelf;

And soon I intend you may go and play,
While I manage this world myself.

But, harness me down with your iron bands,
Be sure of your curb and rein,

For I scorn the strength of your puny hands,
As the tempest scorns a chain.

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LESSON I.-BLESSINGS ON CHILDREN.

1. BLESSINGS on the blessing children, sweetest gifts of Heaven to earth,
Filling all the heart with gladness, filling all the house with mirth;
Bringing with them native sweetness, pictures of the primal bloom
Which the bliss forever gladdens, of the region whence they come ;
Bringing with them joyous impulse of a state withouten care,
And a buoyant faith in being, which makes all in nature fair;
Not a doubt to dim the distance, not a grief to vex the nigh,
And a hope that in existence finds each hour a luxury;
Going singing, bounding, brightening-never fearing as they go,
That the innocent shall tremble, and the loving find a foe;

In the daylight, in the starlight, still with thought that freely flies,
Prompt and joyous, with no question of the beauty in the skies;
Genial fancies winning raptures, as the bee still sucks her store,
All the present still a garden glean'd a thousand times before;
All the future but a region where the happy serving thought,
Still depicts a thousand blessings, by the winged hunter caught;
Life a chase where blushing pleasures only seem to strive in flight,
Lingering to be caught, and yielding gladly to the proud delight;
As the maiden, through the alleys, looking backward as she flies,
Woos the fond pursuer onward, with the love-light in her eyes.
2. Oh! the happy life in children, still restoring joy to ours,
Making for the forest music, planting for the wayside flowers;
Back recalling all the sweetness, in a pleasure pure as rare,
Back the past of hope and rapture bringing to the heart of care.
How, as swell the happy voices, bursting through the shady grove,
Memories take the place of sorrows, time restores the sway to love!
We are in the shouting comrades, shaking off the load of years,
Thought forgetting, strifes and trials, doubts, and agonies, and tears;
We are in the bounding urchin, as o'er hill and plain he darts,
Share the struggle and the triumph, gladdening in his heart of hearts;
What an image of the vigor and the glorious grace we knew,
When to eager youth from boyhood at a single bound we grew!
Even such our slender beauty, such upon our cheek the glow,
In our eyes the life of gladness-of our blood the overflow,
Bless the mother of the urchin! in his form we see her truth:
He is now the very picture of the memories in our youth;
Never can we doubt the forehead, nor the sunny flowing hair,
Nor the smiling in the dimple speaking chin and cheek so fair:
Bless the mother of the young one! he hath blended in his grace,
All the hope, and joy, and beauty, kindling once in either face!
3. Oh! the happy faith of children, that is glad in all it sees,
And with never need of thinking, pierces still its mysteries;
In simplicity profoundest, in their soul abundance bless'd,
Wise in value of the sportive, and in restlessness at rest;
Lacking every creed, yet having faith so large in all they see,
That to know is still to gladden, and 'tis rapture but to be.

What trim fancies bring them flowers; what rare spirits walk their wood,
What a wondrous world the moonlight harbors of the gay and good!
Unto them the very tempest walks in glories grateful still,
And the lightning gleams, a seraph, to persuade them to the hill:
'Tis a sweet and loving spirit, that throughout the midnight rains,
Broods beside the shutter'd windows, and with gentle love complains,
And how wooing, how exalting, with the richness of her dyes,
Spans the painter of the rainbow, her bright arch along the skies,
With a dream like Jacob's ladder, showing to the fancy's sight,
How 'twere easy for the sad one to escape to worlds of light!
Ah! the wisdom of such fancies, and the truth in every dream,
That to faith confiding offers, cheering every gloom, a gleam!
Happy hearts, still cherish fondly each delusion of your youth,
Joy is born of well believing, and the fiction wraps the truth.

W. G. SIMMS.

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