RISE AND PROGRESS

OF

STEAM NAVIGATIO N.

CHAPTER I.

A BRIEF NOTICE OF THE RISE AND PROGRESS OF STEAM NAVIGATION.HISTORY OF THE STEAM ENGINE NECESSARILY INVOLVED IN IT.-THREE PERIODS ONLY REQUISITE TO BE SPECIFIED TO CONVEY A GENERAL KNOWLEDGE OF MOST INVENTIONS: ORIGIN, FIRST IMPERFECT APPLICATION, AND GREATEST IMPROVEMENT.-HERO, OF ALEXANDRIA, 120 YEARS B.C.; MARQUESS OF WORCESTER AND NEWCOMEN, 1653 to 1705; WATT'S SEPARATE CONDENSER, 1765-THE THREE PRINCIPAL EPOCHS OF THE STEAM ENGINE.-ALL THE IMPROVEMENTS OF NINETEEN CENTURIES INSUFFICIENT TO RENDER IT A USEFUL MACHINE, UNTIL WATT'S INVENTIONS.-WATT THE GENIUS OF THE STEAM ENGINE.-ITS POWERS, AND WHAT IT HAS DONE FOR ENGLAND.-SIR WALTER SCOTT AND LORD JEFFREY'S EULOGIUMS.

A COMPREHENSIVE history of Steam Navigation would, unavoidably, embrace a detailed account of those improvements in the engine, which alone led to this application of it. Such an inquiry, however, would far exceed the scope of these observations. Nothing more is intended, as an introduction to its employment in navigation, than to notice, with as much

brevity as will distinctly mark its progress, the three principal periods of the Steam Engine:

The earliest record with which we are acquainted;

The first and continued, though imperfect and limited, application to useful purposes; and

The chief improvements that gave to it its present capacity, and made it spread rapidly among civilized nations.

The first mention of what must certainly be called a Steam Engine, inasmuch as motion could be produced by steam, is the idea of Hero, of Alexandria, 120 years B.C., and described in a work called "Spiritalia seu Pneumatica," under the name of the Eolipyle. Though it has no resemblance to the modern Steam Engine, it is a singular fact, that one of these identical Eolipyles, this ancient mummy of iron, after a sleep of nearly two thousand years, has been resuscitated, and was, not long ago, and probably is at this time, at work in America, under the name of Avery's Rotatory Engine.

Upon the authority of the original Records of the Royal Archives of Simancas, department of Catalonia, it is stated, that a Spaniard, Blasco de Garay, propelled, by steam, “La Trinidad," of 200 tons, in the port of Barcelona, on the 17th of June, 1543, in the presence of Charles V. The Spanish nation is therefore clearly entitled-assuming the authenticity of the record—to the honour of first applying steam to useful purposes; as also to navigation. It is, however, much clearer, that this honour is remarkable chiefly because it stands alone, for it led to nothing; the Spaniards neither continuing its use, nor adding a single improvement at any period of its progress.

From the early period, therefore, of Hero, until the Marquess of Worcester's engine, erected in 1653, to supply the inhabitants of Vauxhall with water, and which, on the 28th

of May, in that year, was seen in operation by Cosmo de Medici, the, Steam Engine can be considered in no other light than as a mere philosophical toy; showing, however, even at that time, its power, though not its docility. This, probably, was the first Steam Engine ever continuously used in this country, or elsewhere: though Sir Samuel Morland is generally considered to have erected the first in 1683. Branca, an Italian, in 1629, suggested the employment of steam to produce motion; but the machine described is simply the Eolipyle: he, therefore, deserves even less honourable mention than Hero.

In 1682, Papin, a Frenchman, invented the safety-valve; and, in 1690, the piston, and method of producing a vacuum by condensing the steam in the cylinder: great advances unquestionably; the foundation, in fact, of the present Steam Engine. His idea of the combination was, nevertheless, rude to a degree. He did not use, even in his experiments, a separate vessel to generate the steam, but applied the fire direct to the cylinder, as will be noticed by and by, when speaking of the different methods of condensation; and, of the extreme importance of the piston he was certainly unconscious, for he not only did not use it, but entirely abandoned it, for an engine of similar construction to that of Savery's.

In 1698, Savery obtained a patent for his steam engine, called the Miner's Friend, though it was not adopted, as implied by its name. He was the first to employ for useful purposes the vacuum resulting from condensation of steam; but even Savery used no piston.

It was at this period that the Steam Engine began to attract more general attention, and occasionally to present abundant evidence of what it might one day become, when a mind should be found powerful enough to give it a safe and useful direction. But it was not until Newcomen's engine, in 1705, that this useful machine deserves much notice or admiration.

Prior to that period it was employed to a very limited extent to raise water. This was effected, not by the rise and fall of the piston, as at present, but by the pressure of the atmosphere upon the water intended to be raised, forcing it up the connecting pipe into a receiver, previously exhausted by the condensation of steam producing a vacuum in it. When the water was got up this distance, limited-owing to an imperfect vacuum-to a rise of about 26 feet, (instead of 34 feet, the height of a column of water sustained in a perfect vacuum by atmospheric pressure,) it was prevented returning by its weight closing the valve, which opened upwards at the bottom of the receiver, through which it had just been forced by the atmosphere. The steam was then let into the receiver, and, by its pressure upon the water therein, caused it to rise through another pipe to the place intended. This could not be more than 68 feet above the receiver, because steam was not, at that period, obtained to exert with safety a greater pressure than 45 lbs. on the square inch. A valve in this pipe, also, opened upwards, and thus prevented the return of the water, by closing with its weight. The steam having thus emptied the receiver, was again condensed by cold water flowing upon the outside, which, causing the vacuum as before, it was immediately followed by the rush of water from the well into the exhausted receiver; and thus the same process continued.

It is apparent, therefore, that to drain deep mines with an engine of this description, several must be employed one above the other, at distances of about 94 feet; 26 feet being, as just described, the height to which atmospheric pressure was equal to force water from the mine into the partially exhausted receiver; and 68 feet being the extent to which it could then be continued above the receiver, by the highest pressure steam that could be safely exerted.

This engine has not been noticed to combine the low and

high-pressure principles, though reversed as regards the latter. Condensation of the steam sufficiently identifies it with the low-pressure engine; but instead of steam being driven into the atmosphere, as in the high-pressure engine, the water in Savery's engine is raised from the receiver, in opposition to atmospheric resistance. This accounts for the narrow limit to its power, because 15 lbs. steam pressure per square inch on the water to be raised from the receiver, is expended merely to equalize the atmospheric resistance to its ascent; consequently, the water will not be raised an inch by such pressure; all above it, however, is available power: for instance, 15 lbs. will only neutralize atmospheric resistance; 15 lbs. more, or 30 lbs. in all, will raise a body of water from the receiver, having a base equal to the surface pressure, 34 feet high; 45 lbs. pressure will raise it 68 feet high, and so on. If, therefore, 15 lbs. be deducted from the total pressure exerted, the remainder will show to what height a column of water can be raised, by allowing 34 feet for every 15 lbs. pressure.

The consumption of fuel by such an engine was necessarily enormous. The steam coming in immediate contact with the water to be raised from the receiver, was partly condensed before it could exert any pressure. To separate the two, a piece of wood, which may be considered a rude sort of piston, was interposed, fitting exactly to the shape of the receiver, and floating on the water in it, and thus some fuel was saved.

Newcomen's improvements on the Steam Engine, form by far the most important feature in this, the second, era of its progress. He first employed the piston to communicate motion, one of the greatest steps to its future usefulness, and which gave to it the form and character that, not long afterwards, led to its being perfected by a single mind. Until Newcomen's engine, none bore any resemblance to the mo