MECHANICAL SYSTEM, for a radically different system of transmissive mechanism, for a system that can develop a considerable portion of the power of the steam in the movement of boats. The variations of the old systems of propulsion that are being continuously tried are worthless, in the very nature of the case, because they are in no sense a remedy for existing inabilities, and because they do not, in any sense whatever, meet the difficulties. STEAM IN 1871 AND 1872. SCREW PROPELLERS. Soon after the Act of April, 1871, to foster and develop the inland commerce of the State, the steam canal-boat _Cathcart_ was tried. She is like the _Niagara_ of 1859, and has not been continued in the trade. The canal-boat _George Barnard_, afterward called the _Andrew H. Dawson_, was tried, and has run through the season of 1872. She has a common propeller in her bow, with a recess from the water-line inclined to twenty feet aft to the bottom. Her propeller, therefore, forces the current against this incline and along the bottom in retardation of its progress. Hence, she cannot be expected to excel former trials. The _Eureka_ is an iron boat, built at Buffalo, with twin-propellers at her bow, set in recesses, at a diverging angle, to throw the water from the bow along the sides of the boat. She is built, by men of canal experience, with compound engines, and was designed to be a superior boat for canal purposes. But her _mechanical currents_ at and against the bow must have a retarding tendency, not compensated by any other considerations. The _George A. Feeter_ is also a twin-propeller, with diagonal, channel waterways on each side for about twenty-five feet, when they merge into a larger channel about five feet forward of the rudder. Her propellers are set in these channels, about ten feet aft of their side openings. With her propellers thus housed, the mechanical currents against the aft-sides of her channels are very damaging to her efficiency. The _Wm. Baxter_ is also a twin-propeller, like the _P. L. Sternburg_, of 1858, and with compound engines, like the _Eureka_ and the _Dawson_. She is built of yellow pine, with easy lines, and so low as to be unable to carry five-sixths of a horse-cargo of wheat or corn below deck, so that her lightness gives help to cargo, and her sharp bow and stern to speed. But her construction and model were long since abandoned by canal-boat builders. The _Wm. Newman_ is a common propeller and double-deck boat, and carries two hundred and ten tons. She is much like the _Ruggles_ of 1858, but has less steam capabilities.