The invention of a mode of constructing furnaces calculated to burn all the smoke given out by the fuel, is usually attributed to our celebrated countryman, Mr. James Watt; but it appears from the volume of the Academy of Sciences, at Paris, for 1699, that some successful experiments were made by M. de la Hire, which had reference to an invention of many years previous date, by Delasme, a French engineer. The latter, we are told, exhibited his furnace tor consuming its own smoke at the fair of St. Germain, in the year 1685. The fire-place of Delasme consisted of a long tube, bent into the form of a syphon, and inverted, the longest leg of which formed a chimney, and the shortest the furnace. The fuel was deposited on a grating near the top of the shortest leg, being supplied from above. Soon after the ignition of the fuel the heat was communicated to the longest leg or chimney, and by that means a current of air was caused to pass downward through the fuel, and under the grate, where the smoke was consumed.