... jerking or irregular motion. The wheel turns both with the flowing and ebbing of the tide, having a sluice-gate and tail-gate on each side, one pair being opened when the other pair is closed. Dryden 's is an undershot-wheel, each float being set at an equal angle with the radius drawn from it to the center. The bottoms of the buckets have narrow openings to admit air as they rise from the water...