The following inventions have been patented this week, as will be found by referring to our List of Claims :— ELECTRO-MAGNETIC ENGINE.—F. Yeiser, of Louisville, Ky., has invented a new engii e, in which electro-magnetism is to be the motive power. The invention consists in a certain system of balanced beams or frames carrying soft iron bars at each end, to be operated upon alternately by two series of electromagnets in such a manner as to receive an oscillating motion, and hav ing combined with them mechanism, through which their oscillating motion is caused to produce the rotary motion of a shaft. ADAPTING ELECTROTYPE PLATES TO CYL-INDEBS—The object of this invention is to print very rapidly from engraved electrotype or other plates. As the first step towards the accomplishment of this object, the inventor proposes to connect the surface of the plate to be printed from into a cylindrical form, that it may be made to rotate, and produce the impression on paper or other substance as the latter moves between it and another rotating surface. The first part of the invention consists in backing the plates with a flexible but inelastic, or very slightly elastic metal or alloy, and when thus backed winding them on the periphery of the printing cylinder by drawing and bending them between the latter and the periphery of the feeding and impression cylinder, so as to make them bear evenly and solidly upon every part of the printing cylinder, and securing them firmly thereto, by which means the plates are made, practically, as much a portion of the printing cylinder as though made of the solid metal of the cylinder. The inventor also applies what he calls a "clearing roller," in combination with the printing cylinder and the inking roller, to remove the superfluous ink from the surface of the plate after the inking cylinder has inked it. He also employs an endless band to clean and polish the surface of the plate between the engraved or sunk portions which produce the impression. The inventor of this valuable improvement is Frederick B. Nichols, of Morrisania, N. Y. TUBES FOR CONVEYING SOUND.—The object of this invention is to collect an adequate volume of sound, and reflect the same through the tube in parallel lines of vibration, provision being made for properly reflecting the sound at the angles of the tube should any be required. This object being attained, sound may be transmitted through tubes much more audibly than by those of usual construction, as the lines of vibration are not, as heretofore, arrested in their progress and neuralized by reflection, in consequence of their zig-zag passage through the tube. It is the invention of R. G. Hatfield, architect, of this city. EXCAVATOR.—This invention is designed for removing mud, sand, or gravel from within the holds of sunken vessels, and also any submerged articles desired to be raised. It consists in forcing a stream of water directly over the objects to be raised, or causing the stream to act at such spots that the sand will be washed away by the stream, and the article exposed and rendered accessible to submarine divers. Eli Brazelton, of St. Louis, Mo., is the inventor.