Nikola Tesla U.S. Patent 514,169 - Reciprocating Engine Patent Wrapper Page 15

60 respectively. I do not consider as of special importance the particular con st ruct ion and arrangement of the cylinder, the piston and the ports for controlling it, except that it is desirable that all the ports, and more especially, the exhaust ports should be made very much larger than is usu ally the case, so that no force due to the action of the steam or campressed air will tend to ret ard or affect the return of the piston in either direction. 42 The pist an B is secured to a piston rod H, which works in suitable stuffing boxes in the heads of the cylinder A. This rod is prolonged on one side and extends through bearings V in a cylinder I suitably mounted or supported in line with the first, and within which is a disk or plunger J carried by the rai H. The cylinder I is without ports of any kind and is air-tight except as a small leakage may occur through the bearings V, which experience has shown need not be fitted with any very considerable accuracy. The cylinder I is surrounded by a jacket K which leaves an open space or chamber around it. The bearings V in the cylinder I, ext and through the jacket K to the outside air and the chamber between the cylinder and jacket is na de steam or air tight as by suitable packing. -5J