INTRODUCTION.

THE great practical use of machinery to a commercial country is so well known, and its superiority to animal force so universally acknowledged and felt in every branch of our manufactures, that but little apology will be necessary for introducing to the man of science and practical artizan, a work, the avowed object of which is, to render the uses and general principles of the Steam Engine familiar to every class of persons. That it has enabled England to support a proud preeminence, both in arts and political power, is equally apparent; and it is a fact much to be deplored, that while some of the least important of the arts connected with domestic life, have been illustrated and explained by men celebrated for scientific research, a description and account of the uses of this stupendous machine, have been left to the Cyclopædias and other works of a general nature.*

attained by the

Sungine, as well as of hery, being the re- it may be advisable, more immediate subject

to compare the various wer that have hitherto been Purpose; and by this method ed to calculate with certainty the most economical mode of en force. To form, however, an mate of the saving thus effected, it Assary to examine, though but briefly, w of animal force and its result as applied ...Query.

Sun the most accurate observations, it ap

, that the physical powers of the human race ater very widely, not only in various individuals, but also in different climates; the value of a man therefore, as a working machine, will not be so great beneath the torrid zone as in the more temperate climate of Europe. This will serve to illustrate the great advantage which our Colonists, particularly in the West Indies, would derive from the more general employment of inanimate force; the day labour of a negro in the sugar countries, amounting to little more than one

third of that performed by an European mechanic.

A labourer working ten hours per day, can raise in one minute a weight equivalent to 3750 pounds one foot high, or about sixty cubic feet of water in the same time; while the power of a horse working eight hours per day, may be correctly averaged at 20,000 pounds. Smeaton states, that this animal, by means of pumps, can raise two hundred and fifty hogsheads of water ten feet high in an hour. It is a well known fact also, that men when trained to running, are able on the average of several days being taken, to outstrip the fleetest horse; and yet it will be seen from the above statement, that his force, if properly applied, is at least six times that of the most powerful man.

The use of water as an impelling power, both for the turning of machinery and other purposes connected with the useful arts, appears to have been known at a very early period. Vitruvius describes a variety of machines for this purpose, the earliest of which were employed merely to raise a portion of the fluid by which they were impelled. The most simple method of applying this element as a mechanical agent, evidently

The principal object to be attained by the employment of the Steam Engine, as well as of every other species of machinery, being the reduction of animal labour, it may be advisable, before we proceed to the more immediate subject of the present work, to compare the various species of artificial power that have hitherto been employed for that purpose; and by this method we may be enabled to calculate with certainty and precision, on the most economical mode of producing a given force. To form, however, an accurate estimate of the saving thus effected, it will be necessary to examine, though but briefly, the amount of animal force and its result as applied to machinery.

From the most accurate observations, it appears, that the physical powers of the human race differ very widely, not only in various individuals, but also in different climates; the value of a man therefore, as a working machine, will not be so great beneath the torrid zone as in the more temperate climate of Europe. This will serve to illustrate the great advantage which our Colonists, particularly in the West Indies, would derive from the more general employment of inanimate force; the day labour of a negro in the sugar countries, amounting to little more than one