9177. Crayssac, D. April 18. [Addition to 1723/13.] Radial - cylinder engines; revolving-cylinder and reciprocating-piston type.-The connecting- rods c of the engine described in the parent Specification are provided with hard surfaces k which bear upon round hard bars h carried by the pistons, and are held in contact with the pistons by cross-pieces i. The inner ends of the rods have eyes carrying hard steel plates c<2>; which bear against rollers sunk in shoulders f<1> on the disks f. The disks f<2> mounted on ball bearings serve to enclose the bearing-surfaces.