- Hydro ad 001
- Hydro ad 002
- Hydro crain bay for assembly of Woodward governors circa 1950 s
- Hydro power plant unit 1-4 showing Woodward governor units.
- Hydro power plant unit-5-7 showing Woodward governor units.
- Hydro turbine
- Hydro-Electric Power history, circa 1924.
- HYDRO-ELECTRIC POWER PLANT HISTORY.
- HYDRO-ELECTRIC POWER PLANT HISTORY.
- HYDRO-ELECTRIC POWER PLANT HISTORY.
- HYDRO-QUEBEC
- Hydroart Manufacturing Company
- Hydroart Turbines
- HYDROELECTRIC DEVELOPMENTS.
- Hydroelectric Power History.