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Preface.

THIS is a most satisfactory book on the SteamEngine a subject interesting to every one. In these days, when there is so much travelling by land and by water, in the steamboat and the railroad car, no one should be ignorant of that powerful agent by which we have almost succeeded in annihilating both time and space. In view of this, we have carefully revised the present work, which is admirably adapted to the Family, or Young People's Library, and may be profitably put into the pocket to be read when in a boat or

car.

NASHVILLE, TENN., June 7, 1855.

The Editor.

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THE

STEAM-ENGINE.

INTRODUCTION.

For the last two hundred years there has been a large class of industrious and intelligent men who have employed themselves in scientific investigations. By them the earth has been explored: they have ascended to the summits of its mountains, and descended into the depths of its cavities. They have measured and weighed the globe itself, and from its strata drawn the materials for the exercise of their ingenuity and skill. With shrewd and patient observation they have combined and separated different substances, searching out their various elements, properties, and affinities. Nothing, in short, has escaped their curiosity and research. The very sunbeam has been stopped by them in its way, and directed through prisms, that they might ascertain its character and composition; which, when discovered, they have applied to copy the forms and colors of the things which the bright beam illuminates. But of all they have done, nothing is more strange, nor more important to the human race, than their investigation of steam, which, by

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an ingenious mechanical contrivance, they have, in THE STEAM - ENGINE, employed as a motive force.

The purposes to which this wonderful triumph of human ingenuity has been applied are numerous and diversified. From depths, inaccessible without its aid, it draws the metal from which other engines may be constructed, and the coal destined to give them activity. By its assistance iron is rolled, drawn, forged, and formed into shapes for machines which it puts into motion, spinning and weaving every article of dress, from the delicate fancy lace to the closely woven woollen cloth. It lifts, draws, bores, drills, planes, saws, and, with an exactitude not to be obtained by any manual skill, may be applied to almost every mochanical process. By its power we are conveyed on land at a speed which, thirty years ago, would have been deemed fabulous; or transported, with ease and comfort, over river, lake, and sea, in defiance of current, wind, or tide. The question seems no longer to be, "What can steam do?" The inquiry rather is, "What remains for it to accomplish?"

This mighty engine is the application of a wellknown and easily understood natural force, but one from which it could scarcely have been imagined that such important results were to be obtained. The vapor which flows in white streams from the spout of a tea-kettle when water is boiling, is the moving power of that mechanism by which such varied labors are performed. To describe the gradual steps by which

the properties of this vapor and their applicability to the wants of social life were discovered, will form one of the main subjects of this volume.

There is no experiment in the whole range of science which would create more curious wonder than the boiling of water and the production of steam, if it were but novel. That water should be put into a close vessel as a heavy fluid, obedient, like all other solids and liquids, to the law of gravitation, and that after a short period of exposure to heat it should burst out as an elastic, bounding vapor, rising and spreading instead of falling, is a phenomenon quite as surprising as the formation of a solid by the mixture of two liquids, or any other marvel of modern chemistry. But it is generally viewed without interest, because it is daily seen, and what little is known about its properties is commonly learned from household tradition, rather than from thought or investigation. Few, however, are so ignorant as not to know that when water has been made hot enough to boil, the heat it continues to receive is employed in converting it into steam, and that this steam has a great expansive power. Now it is this property of expansion which gives steam its mechanical force. The same principle which, on a small scale, causes the cover of the teakettle to rise, will, when steam is generated in larger vessels, and allowed to gather force by accumulation, lift up the most ponderous weights. To the force of this vapor, indeed, there is no limit but the magnitude and strength of the boilers in which it is generated. If steam, however,

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