Mr. R. C. Holmes, says the United States Gazette, has invented a new application of the tiller rope to the wheel for steering vessels, and has prepared a model of the whole application, tiller-frame, wheel, and rope, so that the properties of the invention can be easily discovered. The advantages are that there is no slack made; and, consequently, there is no chafing, and a single hand at the wheel will do the ordinary work of two men. * * * * * ELECTRO-MAGNETIC BOAT. It is stated in some of our exchanges, that Dr. Page, of Washington, has perfected a boat to be propelled by the electro-magnetic power. We know of no man better qualified to produce and introduce successfully such an invention, and we feel assured that whatever enterprise Dr. Page undertakes in that line, will be very apt to go ahead. We hope soon to obtain further intelligence on the subject. * * * * * It is reported that the British government has granted $100,000 per annum to the royal company of Atlantic steamers, for the establishment of a post route to the Pacific, across the Isthmus of Panama. * * * * * IMPROVEMENT IN BOATS. There is a model of a steamboat to be seen on the Chesapeake, invented and constructed by Cyrus Williams, Esq., which is exciting considerable interest among steamboat men. It is in the usual form of a boat, but more flat-bottomed, and much longer in proportion to its width, than the boats now in use, giving it a greater surface to the water, and of course a lighter draught. The improvement is in applying the bridge principle of bearers in supporting length of boats. It looks perfectly feasible. Mr. Williams thinks it will be a great saving of expense, as it takes much less timber, and all of it can be sawed in a mill, being straight stuff. He offers to build a boat on this model, furnishing one third of the stock, and if it does not make 25 miles to the hour, he will forfeit his share. * * * * * CASTING IRON CANNON BY A GALVANIC PROCESS. A hoaxical looking article, under the above caption, is going the rounds, and represents that successful experiments on this subject have been recently made at Berlin. As no description or illustration of the process or principle is given, we leave the subject for those who are ever ready to swallow whatever appears in a newspaper, without regard to probability. * * * * * NEW SHINGLE MACHINE.