15,936. Lehmann, A. Aug. 3. Gas and like engines, rotary. A revolving- cylinder engine has its cylinders in co-axial pairs on opposite sides of the crank-shaft, the piston - rods being attached to a transverselyslotted yoke b in which the crank-shaft c works ; the slot b in the yoke is not quite at right-angles to the cylinder axis, so that the pistons dwell at the end of their strokes. The engines work on a two-stroke cycle, a charge being drawn through the crank-shaft and port i into the space k, whence it is forced through a chamber l, passages m, n, and ports o into the cylinder and expels the exhaust through ports u which alternate with the ports o. A flange on the head of the piston is notched to uncover the ports o, and the ports p between the notches have grooves p to direct the incoming charge over the cylinder walls. The chambers k are separated from the crank chamber d, which is fitted with stuffing-boxes g and is supplied with oil up to the level of the overflow pipe t through passages q, r, s. Some oil enters the charge inlet i through the pipe t. The frame turns about the crank-shaft on roller bearings as shown.