the Machine of Marly, formerly considered the most powerful engine in the world, when first erected lost seven-eighths of its power from friction, and other causes; while the overshot water-wheel which can act only in favourable situations, produces nearly eight-tenths of the force employed. Now it is stated by Dr. Desaguliers, that the atmospheric engine working at Griff-mine, nearly a century back, produced full twothirds of effective force for the power employed; and this too at a comparatively moderate expense. We find, farther, that an hundred weight of coals burned in an engine on the old construction, would raise at least twenty thousand cubic feet of water twentyfour feet high; an engine with a twenty-fourinch cylinder doing the work of seventy-four horses. From this it will be seen that a bushel of coals is equal to two horses, and that every inch of the cylinder performs nearly the work of a man.

An engine upon Captain Savery's plan, constructed by Mr. Keir, has been found to raise nearly three millions of pounds of water one foot high with a single bushel of coals ; while the best engine on Newcomen's principle will raise ten millions, and Mr. Watt's

engine upwards of thirty millions of pounds, the same height. If we add to the advantage gained by the employment of so cheap a prime mover, the vast concentration of force thus brought into immediate action, its value may easily be appreciated.

One of the largest engines yet constructed, is now in action at the United Mine in Cornwall; it raises eighty thousand pounds. one hundred feet in height per minute: and to effect this enormous labour, it only requires about thirty pounds of coal for the same period of time.

To the mining interests this valuable present of Science to the Arts has been peculiarly acceptable; as a large portion of our now most productive mineral districts must have long ere this been abandoned, had not the Steam Engine been employed as an active auxiliary in those stupendous works. In draining of fens and marsh lands this machine is in the highest degree valuable; and in England, particularly, it might be rendered still more generally useful. In practice it has been ascertained that an engine of six-horse power, will drain more than eight thousand acres, raising the water six feet in height;

+

while the cost of erection for an engine for this species of work, including the pumps, will not exceed seven hundred pounds. This is more than ten windmills can perform, at an annual expenditure of several hundred pounds; while, in the former case, the outgoings will not exceed one hundred and fifty pounds per annum.

To the mariner, also, the Steam Engine offers advantages of a no less important and novel nature than those we have already described. By its use he is enabled to traverse the waters, both against wind and tide, with nearly as much certainty, and, as the machinery is now constructed, with much less danger, than by the most eligible road conveyance.

In proof of the speed of these vessels, it may be sufficient to state that the passage from or to London and Margate, which is more than eighty miles, by water, is often performed in the short space of six or seven hours! It too frequently, however, happens that the faults of any new invention are unjustly magnified, while its real advantages are seldom duly appreciated; and this axiom has been fully verified, in the clamour so unjustly raised against the application of the Steam

Engine to nautical purposes.

Accidents

are now, however, of but rare occurrence; and it is more than probable, that the great improvements that have been made in the boiler and safety-valve, will effectually secure these parts of the engine from a recurrence of those tremendous explosions, which unfortunately characterized the first introduction of Steam Navigation.

And, lastly, the political economist must hail with the most heartfelt gratification, the introduction of so able and efficient a substitute for animal labour as the Steam Engine. It has been calculated that there are at least ten thousand of these machines at this time at work in Great Britain; performing a labour more than equal to that of two hundred thousand horses, which, if fed in the ordinary way, would require above one million acres of land for subsistence; and this is capable of supplying the necessaries of life to more than fifteen hundred thousand human beings.

INTRODUCTION

CONTENTS.

iv.

CHAPTER I.

Nature of Steam-Application of it as a moving powerBrancas-Marquis of Worcester-Sir Samuel MorlandPapin-Savery-Newcomen-Hulls-Falck-Amontons

Deslandes-Francois.

CHAPTER II.

PAGE 1

Boulton and Watt-Cartwright-Smeaton-Hornblower -High-pressure Engine-Woolf's Improvements-Rotatory Engines-Kempel-Sadler-Cooke-Bell-crank EngineEmployment of the Steam Engine in North America and the Colonies-Locomotive Engines

CHAPTER III.

25

Introduction and Improvements effected by Hulls-Duquet-Juoffroy-Fulton-Miller-Symington-StanhopeLinnaker-Thames and Clyde Boats-Progress of Steam Navigation in America...

CHAPTER IV.

53

Abstract of Evidence before a Select Committee of the House of Commons on Steam Navigation ..

CHAPTER V.

71

Cylinder and Piston-Condenser-Air-pump-Barometer and Steam-Gauge-Working Beam-Parallel Motion