STEAM-NAVIGATION. The propulsion of ships and boats by the expan sive force of steam. Amongst the innumerable advantages derived from the introduction of steam as a motive power, its application to the purposes of navi gation very far surpasses all others in importance. 14 (u our ablest writers and political economists admit,) highly beneficial consequences have resulted, and will continue to flow, from the great improvements made and making in our internal communications, it neceesarlly follows, that by extending times facilities from a single community to those of the various nations of the earth, and combining their interests by a rapid interchange of intelligence and productions, the moat important benefits must follow. In reference to our increased powers of transition by steam from place to place, an eloquent writer has observed,— " The concentration of mind and exertion which • great metropolis always ex hibits, will be extended in a considerable degree to the whole ream. The same effect will be produced as if all distances were lessened in the proportion in which the speed and cheapness of transit are increased. Towns at present removed some stages from the metropolis will become its suburbs; others, now at a day's journey, will be removed to its immediate vicinity ; business will be carried on with as much ease between them and the metropolis, u it is now between dis tant points of the metropolis itself. Let those who discard speculations like these as wild and improbable recur to the state of public opinion at no very remote period, on the subject of steam-navigation. Within the memory of persons who have not yet passed the meridian of life, the of traversing, by the steam-engine, the channels and seas that surround and intersect these islands, was regarded as the dream of enthusiasts. Nautical men, and men of science, re jected such speculations with equal incredulity, and with little less than scorn for the understanding of those who could for a moment entertain them. Yet we have witnessed steam-engines traversing, not these channels and seas alone, but sweep .ng the face of the waters round every coast in Europe. The seas which inter pose between our Asiatic dominions and Egypt, and those which separate our own shores from our West Indian possessions, have offered an equally ineffectual barrier to its powers. Nor have the terrors of the Pacific prevented the En terprise from doubling the Cape, and reaching the shores of India. If steam be not used as the only means of connecting the most distant points of our planet, it is not because it is inadequate to the accomplishment of that end, but because the supply of the material, from which, at the present moment, it derives its powers, is restricted by local and accidental circumstances." The in troduction of steam to propel ships has not merely had the effect of shortening voyages considerably, but it has lessened the obstacles and dangers of a voyage in the same; and in short trips, steam-vessels now generally effect them with near y the same punctuality and regularity as journeys upon land.
Long prior to the introduction of the steam-engine as a motive power to drive machinery, a variety of contrivances were suggested, and some carried into prac tice, to propel vessels in a calm ; such as paddles operating like ducks' feet, by pushing out at the stern against the water; the revolution of wheels with float ; the forcing out of water backwards, by means of pumps, &c. ; but the actuating force in these cases was not steam, but generally that of manual labour, through the medium of common mechanism. The earliest direct proposition for the employment of steam as a motive force, that we remember to have met with, occurs in the ifieer's Friend, written by the celebrated Captain Savery, and published in 1702: but it does not appear that Savory ever went beyond suggesting the possibility of the application. Dr. Pepin, however, about the
same period published, amongst other interesting projects, a method of propelling vessels against the wind, by means of steam. During his residence in England, this ingenious Frenchman had witnessed en interesting experiment made on the Thames, in which a boat, constructed from a design by the Prince Palatine Robert, was fitted with revolving oars, or paddles, attached to the two ends of a long axle going across the boat, and which received its motion from a trundle working in a wheel turned round by horses. The velocity with which this horse boat was impelled was so great, that it left the King's barge, manned with six teen rowers, far a-stern in the race of trial. "This," observes Mr Stuart, " was the mechanism he wanted; but before he could avail himself of so fine a thought, it was necessary that he should contrive to convert the alternate motion of his piston-rod into a continuous rotary one. To one so well acquainted with mechani cal contrivances there could be little difficulty in doing this ; watchmakers prac tised various modes of converting the one motion into the other, and the one which occurred to Pepin was suggested by clock-work mechanism. A rack was placed on the piston-rod, working into a pinion fastened on the axle of the revolving paddles. He employed two or three steam cylinders, and when the piston of the one was ascending, that of the other was working downwards ; and as they would give contrary motions, one was detached while the other was in action; and by this means the motion could be made continuous and tolerably regular." Whether Dr. Pepin carried his project beyond that of making a model, does not appear from any authority with which we are acquainted. The next per son that we meet with on record, was Dr. John Allen, who in 1730 published a treatise entitled Spadini= klawgrapkia, or a brief Narrative of several New Inventions. In this publication the Doctor describes severed new inventions, and observes, that in them " the motion was communicated by machinery working without the ship, something analogous to oars or paddles, or by the re volution of wheels turned by a capstan plead within the ship;" on the con trary, no part of the Doctor's was placed on the outside of the vesseL His method was to form a tunnel or pipe, open at the stern of the vessel, and by means of a pump to force water or air through it into the sea • and by the re action which this would occasion, the ship would be driven forward; thereby accurately " imitating what the Author of nature has shown us in the swimming of fishes, who proceed in their progre 've motion, not by any vibration of their fins as oars, but by protrusion with their tails ; and water-fowls swim forward by paddling with their feet behind their bodies." The Doctor carried his scheme into practice on a canal, with a boat of considerable dimensions, working his pumps by manual labour; he however suggested the employment of a steam engine as a preferable power, and proposed its application to a vessel of 1400 or 1500 tons burthen. This project of Dr. Allen's has been repeatedly proposed and published since by various individuals, and what is very remarkable, several patent* have been taken out by different individuids for precisely the same thing, owing principally to the agents employed to procure the grants being ignorant of the mechanical inventions.