side cylinders; and in fig. 118 a longitudinal section of the same: c c the fire-box; d d the flue-tubes; ss the smoke-box; ee the conical blast pipe, the opening of which is regulated by the levers as in the drawing; mm the steam-dome, n n the steam-pipe; r the regulator dome; othe STEAM-NAVIGATION AND THE MARINE ENGINE. 127 regulator, consisting of a spindle-valve, actuated on by the lever o', admitting steam to the cylinder through the pipe o" o"; 7l the steam space above the tubes; pp the lock-up spring safety-valve; fg the funnel; ii, hh, kk, the "spark-arrester." The curved arrows show the direction of the heated air; the sparks being deposited in the curved vessels ii, the heated air and steam passing out at the vertical apertures The eccentric-rods and gear for working the valves, &c. are shown k k. CHAPTER VI. STEAM-NAVIGATION AND THE MARINE ENGINE. UNDER the present division of our treatise we propose to give a few historical notes as to the introduction of the steam-engine for the purposes of navigation, preliminary to the illustrations and descriptions of the modern "marine engine." From the limited space now at our disposal, we shall be prevented from going so deeply into the historical details as might, by some, be considered necessary; but we shall nevertheless endeavour to notice their most important features. For many years previous to the application of the steam-engine to the propelling of boats, the substitution of sundry mechanical contrivances for sails had been a favourite object with mechanics. The most noticeable of these was the revolving wheel with float-boards on its periphery: this, modified somewhat in its arrangements and construction, is identical in principle with the "paddle-wheel" of the modern steam-boat. The various contrivances introduced for boat-propulsion were actuated either by manual labour or that of horses, through the intervention of simple mechanical arrangements. The earliest notice we have of an attempt to substitute the power of steam for these methods of working is that of Blasco de Garay, to whose invention we have already alluded in the first chapter. Captain Savery, in the Miner's Friend, alluded to the capability of steam as a power for moving steam-boats: but it does not appear that he entered further into the matter than making a mere suggestion. Denis Papin, during his residence in England, is said to have constructed a model by which a steam-piston moving in a cylinder gave motion to the axle of the paddle-wheels; 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 descending; 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. In 1737 Jonathan Hall published "a description and draught of a newinvented machine for carrying vessels or ships out of or into any harbour, port, or river, against wind or tide, or in a calm." In this steam-boat the engine used was an atmospheric one, rotatory motion being obtained by a continuous arrangement of pulleys and cords or bands. We give in fig. 123 a diagram illustrative of the general appearance of this boat. From the imperfect mechanical arrangements, and the defects of the atmospheric as a rotative engine, this attempt at steam-boat propulsion was soon abandoned, if indeed it ever went beyond a mere speculation on paper. Passing over various unsuccessful attempts made in America by Fitch and Ramsay, in 1785-1793; the Earl of Stanhope in England, 1795; and of the Chancellor Livingstone and the celebrated Brunel on the Hudson in America, in 1797,-we proceed to notice the first successful steamengine. We must, however, go back for a few years prior to the lastmentioned date. In 1787, Mr. Patrick Miller, of Dalswinton, a gentleman who devoted much of his time to experiments in the improvement of artil lery and naval architecture, published a description, with drawings, of a "triple vessel moved with wheels." Convinced that, to give his invention every fair chance, it was necessary to employ some force greater than that of manual labour, he threw out a suggestion to employ the steam-engine for the purpose of moving the wheels; the force of steam, amidst other means proposed, presented itself, however, to his mind "as at once the most potent, the most certain, and the most manageable." "In Miller's family," says his son, in the narrative published in the Edinburgh Philosophical Journal in 1824, "there was at this time, as tutor to his youngest children, Mr. James Taylor, who had bestowed much attention on the steam-engine, and who was in the custom of assisting Miller in his experiments on naval architecture and the sailing of boats. One day, in the very heat of a keen and breathless contest in which they were engaged with a boat on the Leith establishment, this individual called out to his patron, that they only wanted the assistance of a steam-engine to beat $ SYMINGTON'S STEAM-BOAT. 129 their opponents; for the power of the wheels did not move the boat more than five miles an hour. This was not lost on Miller, and it led to many discussions on the subject; and it was under a very confident belief in its success that the allusion was made to it in the book already mentioned. In making his first experiments, Miller deemed it advisable in every point of view to begin upon a small scale, yet a scale quite sufficient to determine the problem which it was his object to solve. He had constructed a very handsome double vessel with wheels, to be used as a pleasure-boat on his lake at Dalswinton; and in this little vessel he resolved to try the application of steam." To aid him in the fitting up of the steam-engine, he secured the services of an engineer to whom he was introduced by Taylor, one whose name will be handed down to posterity as the engineer to whom practical steam-navigation is mainly indebted for its introduction,William Symington. It was to this latter individual, an engineer of great practical attainments, that the task of fitting up the steam-engine was intrusted. In the autumn of the same year in which he was employed, the steam-engine, having brass cylinders of four inches diameter, was placed on board the little pleasure-boat. "Nothing," says Mr. Miller in his narrative, "could be more gratifying or complete than the success of this first trial;" and while for several weeks it continued to delight Miller and his numerous visitors, it afforded him the fullest assurance of the justness of his own anticipation of the possibility of applying to the propulsion of his vessels the unlimitable power of steam. On the approach of winter, the apparatus was removed from the boat, and placed as a sort of trophy in his library at Dalswinton, and is still preserved by his family, as a monument of the earliest instance of actual navigation by steam in Great Britain. In the succeeding year, a larger boat, sixty feet long, was tried on the Forth and Clyde Canal; the engines and machinery were constructed at the Carron Iron Works, near Falkirk; and in December, 1789, "in the presence of a vast number of spectators, the machinery was put in motion." This second trial promised to be every way as prosperous as the first. It happened unluckily, however, that the revolving paddles had not been made of sufficient strength; and when they were brought into full action, several of the float-boards were carried away, and a very vexatious stop was for that day put to the voyage. The damage was repaired, and on the 25th December the steam-boat was again put in motion, and carried along the canal at the rate of seven miles an hour, without any untoward accident; although it appeared evident that the weight of the engine was an over-burden for the vessel (her planking being only three-quarters of an inch thick), and that under such a strain it would have been imprudent to venture to sea. The experiment, however, was again repeated on the two following days; and having thus satisfied himself (Miller) of the practicability of his scheme, he gave orders for unshipping the apparatus, and laying it up in the storehouses of the Carron Works." In consequence, as it appears from the statements in the narrative by his son, Miller was led to abandon further experiments, partly from the large expenses which the first trial had cost him, and partly from his attention becoming much directed to agricultural pursuits. In 1801, Symington, patronised by Lord Dundas of Kerse, started a steam-boat on the Forth and Clyde Canal, for the purpose of towing boats. In fig. 120 we give a drawing of Symington's first engine, and in fig. 121 a drawing of the second and improved design; for these we are indebted to the courtesy of Mr. William Symington, of London, the son of the inventor. The following is the description of the various parts : In fig. 120, a a are the evlinders, b the boiler, c steam-pipe, d d airpump rods, e e connecting-chains, ff direction-pulleys, g g paddle-wheels, situated and wrought in a trough extending from stem to stern of the boat, and allowing free ingress and egress to the water; hh ratchet-wheels, for communicating motion to the paddles; ii the water-line. In fig. 121, a the cylinder, b the boiler, c steam-pipe, deduction-pipe, e condenser and air-pump, g hand-gear and pump-rod, h piston and connecting-rod, supported by the friction-wheels; the rod which communicates motion to the air-pump lever; j crank; k paddle-wheel, situated in a cavity in the centre of the stern of the vessel; paddle-wheel cavity, open behind and below to the water; m steer-wheel; n n flotation-line. This boat was steered by two rudders connected by iron rods, and wrought in the prow by the steer-wheel. fig. 121. We come now to notice the exertions of another individual who occupies an important place in the history of steam-navigation - Robert Fulton, an American. Passing over various matters connected with this |