An invention which promises to be one ot the greatest utility is described in the '? Hartford (Conn ) Times. It is a machine for boring tunnels, the work of a Mr. E. Talbot, a practical mechanic, who states that in the rapidity and completeness of its execution, it will surpass every instrument of the kind yet conceived. Worked into its own machinery is an engine of sixty horse-power, which drives four piston rods, horizontally, and these turn four halt circle plates, of stout proportions, furnished with circular revolving blades. These four plates are turned with exactness about one-fourth of a circle and back, and are all set upon a revolving plate of about ten teet in diameter, and as thus set, cut a circle of seventeen feet in diameter. The machine weighs about eighty tons. The motion obtained by this invention is novel—entirely new. By it the revolving knives, each running its quarter circle, cut completely from the centre to the circumference, and they do their work steadily and surely, cutting a round hole with astonishing celerity.