ClipArt ETC
"Thus constructed, this wheel moves equally well whether the water acts on one or the other side of the boards, and hence is employed for tide wheels, which turn in one direction when the tide is going out, and in the other when it is coming in." -Comstock 1850

Undershot Wheel

"Thus constructed, this wheel moves equally well whether the water acts on one or the other side of…

"Waterwheel where the lowest flat-board is submerged in the running water. The water is often given its power from a slight inclination. This wheel is also often powered by the running water issued by a dam." —Quackenbos 1859

Undershot Wheel

"Waterwheel where the lowest flat-board is submerged in the running water. The water is often given…