On Friday last, while visiting the steamboat wharf, a curiosity was presented to our view in the shape of a new steamer, designed by the well-known engineer, Mr. David Napier, of London. We were naturally anxious to witness the performance of this new ac-quatic traveller, and having a few hours to spare at the time, we started with her on g trip to Dumbarton and back. ' She is about the same length and breadth as the other Dumbarton boats, but in other respects differs widely from any of them, or any of the other boats on the Clyde. There is a swell on each side of her, under which the paddles work, but no elevation in the shape of paddle-boxes, which are so small in diameter, that they do not rise much above the level of the deck ; her bulwarks running all round on the level ; her engine-room is elevated about three or four feet above the deck, and immediately behind it, and about the same height, is a platform tor the pilot, who steers her with a horizontal iron wheel of simple construction. Close by the pilot there are two long iron handles coming up from the engine room, by which the captain regulates, stops, or reverses the motion at pleasure and with ease, the engineer having nothing to do with that process as has hitherto been the case.— We will not attempt any minute description ot the engine ; suffice it to say thafit stands in a small space—perhaps that of a parlor table, and bears no resemblance to any engine we have ever seen previously. Its outward appearance is a somewhat complicated mass of pipes, with two horizontal cylinders, or steam chests, into each of which a large slide works perpendicularly. The paddle shaft emanates from the ends ot the steam chest or cylinder, and has four eccentrics on it, which appeared to do the work of cranks. The paddle wheels have only four floats on each. She made the down run in one hour and forty minutes, and the up in one hour and fifteen minutes—stopping- at Renfrew in both cases. The engineer told us that he expected a much higher speed yet—that being her first day ; besides he informed us that he required only one wagon of coals to perform two trips from Glasgow to Dumbarton and back.— What will be the result of this scheme we know not, neither are we prepared to give any opinion on the engine. We are favorable to the small number of floats, providing the diameter of wheel was much larger, and the fltfete of a better form. [The above is from the " North British Mail." The distance which she made in one hour and fifteen minutes is at least 23 miles ; this is fast running, but not quite as fast as some of our North River boats.