The two sets of paddle blades shown on Schilling's model "are so arranged that they alternate with each other, one set being in action while the other is carried back through the air, and thereby a continuous action of the propeller is produced." Schilling does not detail why his device was suitable for canal boats.
Schilling was a locksmith in New York City.
Cornelius Schilling, Propulsion of Canal-Boats, U.S. patent no. 119,792, Oct. 10, 1871.
Cornelius Schilling, Propelling Apparatus, U.S. patent no. 106,512, Aug. 14, 1870.
Trow's New York City Directory, 1871