the motion of the vessel, was lately presented to the Society of Arts, by Mr. Dickson, who received the silver medal for the above communication.

Mr. D. states, that the great utility of this improvement consists in its application to sailing vessels: for instance, suppose a steam vessel to be going direct against the wind by means of the whole power of her steam engine, and that the wind should change and become favourable, the propellers may, by these means, be immediately raised out of the water, and the vessel allowed to have the whole effect of the sails, thereby saving the expense of fuel. All steam vessels now in use, experience so great an impediment from the propellers being always in the water, as to render sails of no benefit. Another advantage will be derived when there is only a gentle breeze in the vessel's favour, as the propellers can be set to work, which will take hold of the water at pleasure, and thereby unite the power of the steam to that of the wind, which will secure the passage in the given time, at much less expense, as the engine will only consume fuel in proportion to the labour it has to perform. A farther advantage will be found when the vessel has only a side wind; for, by the use of this contrivance, one of the propelling wheels can be worked with its full power in the water, and the other entirely lifted out, if necessary.

For the purpose of accurately trimming the ves

sel, Mr. Dodd recommends the use of a tank or cistern, placed beneath the projecting deck on each side the vessel, the water ballast for which may be raised by the working of the engine. This, on being discharged by means of a plug, would give a preponderance to the opposite side of the vessel, and as it would be placed at the end of a lever, the fulcrum of which is the keel, a small quantity of water would have considerable effect. A contrivance nearly similar to this, has been adopted for a considerable period of time on board one of the Gravesend steam vessels. It consists in the use of a small carriage made to contain an iron cable, which is occasionally employed to moor the vessel, and its weight is such that the vessel may readily be trimmed by moving it from side to side.

Mr. Maudslay has lately constructed a large engine for a steam-boat invented by Mr. Brunel, which has two cylinders acting alternately upon different cranks, formed upon the same axis at right angles to each other, so that the motion is continued without the action of a fly-wheel. In this engine, one boiler is placed between the two cylinders, and one air-pump and condenser exhaust them both; so that by these means an engine of considerable power is contained in the smallest possible space.

Some idea of the prevalence of steam navigation in the more northern parts of our island, may be formed from the following estimate of the number

of passengers who have availed themselves of this species of conveyance in the course of one year. On the Forth and Clyde canal, between Glasgow and Edinburgh, 94,250; between Glasgow and Paisley, by the Ardrassan Canal, 51,700; and from Glasgow, along the Monkland canal, 18,000. Steam-boats of a large size are now employed in the Adriatic. One (La Carolina) goes regularly every second day from Venice to Trieste; another (L' Eridano) passes between Pavia and Venice, and with such celerity, that the voyage is accomplished in thirty-seven hours.

We have now to notice the labours of our transatlantic brethren in this important branch of naval engineering. Profiting by the hints thrown out both by the Marquis de Jouffroy and Mr. Miller, Fulton, who had also seen Symington's boat, ordered an engine capable of propelling a vessel to be constructed by Messrs. Boulton and Watt. This was sent out to America and embarked on the Hudson in 1807,* and such was the ardour of the

* Its first appearance on these waters, is thus described by the biographer of Fulton.

"She had the most terrific appearance, from other vessels which were navigating the river, when she was making her passage. The first steam-boats, as others yet do, used dry pine wood for fuel, which sends forth a column of ignited vapour many feet above the flue, and whenever the fire is stirred a galaxy of sparks fly off, and in the night have a very brilliant and beautiful appearance. This uncommon light first attracted the attention of the crews of other vessels. Notwithstanding the wind and tide were adverse to its approach they saw with astonish

F

Americans in support of this apparently new discovery, that the immense rivers of the new world, whose great width gave them considerable advantages over the canals and narrower streams of Europe, were soon navigated by these vessels.

The city of New York alone possesses seven steam-boats, for commerce and passengers. One of those on the Mississippi passes two thousand miles in twenty-one days, and this too against the current which is perpetually running down. The above boat is 126 feet in length, and carries 460 tons, at a very shallow draft of water, and conveys from New Orleans, whole ships' cargoes into the interior of the country, as well as passengers.

The following list of steam-boats now in operation on the river Mississippi, and its tributary streams, has been published by Mr. Robinson.

ment that it was rapidly coming towards them; and when it came so near as that the noise of the machinery and paddles was heard, the crews in some instances shrunk beneath their decks from the terrific sight, and left their vessels to go on shore, while others prostrated themselves, and besought Providence to protect them from the approaches of the horrible monster, which was marching on the tides, and lighting its path by the fires which it vomited.

CHAPTER IV.

Abstract of Evidence before a Select Committee of the House of Commons on STEAM NAVIGATION.*

Mr. BRYAN DONKIN was called in and
examined.

WITNESS went down to Norwich, as a volunteer, to inquire into the cause of the explosion of a steamboat. Was accompanied by Mr. Timothy Bramah and Mr. Collinge. Was of opinion that the immediate cause of that explosion had been the use

* The Committee commenced its sittings May S, 1817, and consisted of the following highly respectable individuals:Charles Harvey, Esq. in the chair; Mr. William Smith, Mr. Davies Gilbert, Sir Martin Folkes, Sir James Shaw, Sir William Curtis, Sir Charles Pole, Mr. Alderman Atkins, Mr. Williams Wynn, Sir Edward Kerrison, Mr. Lacon, Mr. Shaw Lefevre, General Thornton, Mr. Edward Littleton, Mr. Finlay, Mr. Leader, Mr. Alderman Smith, Mr. Wrottesley, Mr. Barclay, Sir James Graham, Mr. Swann, Mr. Charles Dundas, Mr. Holmes, Mr. Thompson, and Mr Bennet.

On the 14th of the same month, Sir Matthew Ridley and Mr. Ellison were added to the Committee.