He is considered one of the precursors of rotary engines along with Seguin, Verdet, Adams-Farwell.

-It is known that Balzer was a watchmaker at Tiffany's in New York and that he later designed a vehicle powered by a rotary engine, with four wheels, as early as 1894.

“Stephen Balzer's vehicle”

-Together with Charles Manly -another precursor- they designed the rotary engine, converted to a fixed engine, for Langley's experiments in his “Aerodromes”. See Balzer and Manly.

“Balzer-Manly”

From appendix 6: Balzer was a motor-racing pioneer, who along with Manly made the engines for Langley's Aerodrome.

“The Balzer-Manly, front and rear view”

-Before he had built smaller engines (See Manly).

-It is a five-cylinder rotary engine, rotating on two transverse supports, which can be seen clearly in the above photographs.

-Perhaps the most "modern" part was that of the combustion chambers attached to the cylinder.

-It had three valves, automatic exhaust and inlet valves, and another controlled and bigger valve that communicated the sub-chamber with the main-chamber. Its operation -at least for the drawing- is not rather clear.

“Balzer-Manly prechamber” (AEHS)