National Geographic : 1928 Mar
Photograph by A. E.Young LOWERING A PASSENGER STEAMER FROM THE LAKE SUPERIOR TO THE LAKE HURON LEVEL, ADROP OF ABOUT 20 FEET The gates behind the steamer having first been closed, the valves of the lock are opened and the water gradually flows out through the bottom and into the fore bay. When the level of the water inside the lock reaches that of the water on this sideofthe foreground gates, they will swing open and the ship will be ready to continue its journey on the Huron level. Sault Ste. Marie (see, also, page 324).