Nikola Tesla U.S. Patent 517,900 - Steam Engine Patent Wrapper Page 14

86 Substitute A WHAT I CLAIM IS: 1. The combination with the cylinder and piston. of engine having duotsar) ports for the admission and dust kar Fb.24 94 exhaust of the steam ogas under pressure, of a valve for controlling said ports connected with or constituting the piston of an independent controlling engine of constant. period, substantially as described. do 2. The combination of an engine cylinder, a comis fret piston adapted to reciprocate therein a slide valve for controlling the admission of steam to said cylinder, and an in de pendent controlling engine of constant period operatively connected with said valve. 3. The combination with the cylinder, piston and valve mechanism of a main or working engine, of an independent controlling engine comprising a cylinder, a piston connected with the valve mechanism of the main engine, and a spring acting upon the said piston and controlling the period of its reciprocation, as set forth. 4. The combination with a cylinder and a piston adapted to be reciprocated by ste an or a gas under pressure of a cylinder and a plunger therein reciprocated by the piston and constituting with its cylinder an air spring, and an open jacket or receptacle around the said cylinder and containing water to preserve the temperature of the air spring uniform, as set forth. -9