Hamilton Hydraulic, or the Hamilton & Rossville Hydraulic -- a system supplying water power to shops and mills -- spurred one of Hamilton's greatest periods of industrial and population growth (1840-1860). Henry S. Earhart, a merchant and civil engineer, is credited with the idea of bringing water from the Great Miami River north of Hamilton into the town as a source of power for nonexistent industries. Much of the preliminary work was by John W. Erwin, an engineer who also collaborated with Earhart and John C. Skinner in building turnpikes, railroads, other waterway projects and civic improvements. The Hamilton and Rossville Hydraulic Company was directed by Gov. William Bebb, Lewis D. Campbell, John Woods, Laomi Rigdon, Dr. Jacob Hitell, Earhart, Erwin and Skinner and other leaders.
The hydraulic began about four miles north of Hamilton on the river, where a dam was built to divert water into the system. Nearby, two reservoirs stored water for the hydraulic, whose main canal continued south along North Fifth Street to present Market Street (then Stable Street). There it took a sharp west turn to the river at the present intersection of Market Street and North Monument Avenue, between the former Hamilton Municipal Building and the former Hamiltonian Hotel. The first water passed through the system in January 1845. As the water flowed through the canal, it turned millstones in the hydraulic. The project had been a risky one because there were no shops along its course to use the power when the company was organized in 1842. The gamble paid off. Several small industries were built on the hydraulic in the 1840s. One was the Miami Paper Mill, later known as the Beckett Paper Co.
The hydraulic remained a principal source of power for Hamilton industries through the 1870s when the stationary steam engine became affordable. Later, most of the canal was covered and/or filled. The hydraulic attracted Henry Ford to Hamilton after World War I when he sought a site for a tractor factory. Ford built a plant -- which soon converted to producing auto parts -- at the north end of North Fifth Street so it could take advantage of power provided by a branch of the hydraulic.
A Rossville hydraulic also was built, but never achieved the success of the Hamilton system. Construction started in 1849 on the Rossville hydraulic, which originated at a dam across the river near the present intersection of North B Street and West Elkton Road. It continued south along the west bank of the river to present Wayne Avenue, where the borrowed water returned to the Great Miami River. John W. Erwin, who helped plan the Hamilton Hydraulic, also was a key figure in developing the Middletown Hydraulic, which opened in 1852.