During the general lassitude of mechanical exertion which succeeded the American Revolution, We utility of steam-engines appears to have been forgotten; but the subject afterward started into very general notice in a form in which it could not possibly be attended with success. A sort of mania began to prevail, which, indeed, has not yet entirely subsided, for impelling boats by steam-engines. Dr. Franklin proposed to force forward the boat by the immediate application of the steam upon the water. Many attempts to simplify the working of the engine, and more to employ a means of dispensing with the beam in converting the _libratory_ into a rotatory motion, were made. For a short time, a passage-boat, rowed by a steam-engine, was established between Borden-town and Philadelphia, but it was soon laid aside. The best and most powerful steam-engine which has been employed for this purpose--excepting, perhaps, one constructed by Dr. Kinsey, with the performance of which I am not sufficiently acquainted--belonged to a gentleman of New York. It was made to act, by way of experiment, upon oars, upon paddles, and upon flutter-wheels. Nothing in the success of any of these experiments appeared to be sufficient compensation for the expense and the extreme inconvenience of the steam-engine in the vessel. There are, indeed, general objections to the use of the steam-engine for impelling boats, from which no particular mode of application can be free. These are: First. The weight of the engine and of the fuel. Second. The large space it occupies. Third. The tendency of its action to rack the vessel, and render it leaky. Fourth. The expense of maintenance. Fifth. The irregularity of its motion, and the motion of the water in the boiler and cistern, and of the fuel-vessel in rough water. Sixth. The difficulty arising from the liability of the paddles and oars to break, if light, and from the weight, if made strong. Nor have I ever heard of an instance, verified by other testimony than that of the inventor, of a speedy and agreeable voyage having been performed in a steamboat of any construction. I am well aware that there are still many very respectable and ingenious men who consider the application of the steam-engine to the purpose of navigation as highly important, and as very practicable, especially on the rapid waters of the Mississippi, and who would feel themselves almost offended at the expression of an opposite opinion. And, perhaps, some of the objections against it may be avoided. That founded on the expense and weight of the fuel may not, for some years, exist on the Mississippi, where there is a redundance of wood on the banks; but the cutting and loading will be almost as great an evil.