There are overshot water-wheels and undershot. In the one case the motive power falls from above, in the other the water turns the wheel from below; the first is the more powerful. Men, like wheels, are turned by forces from various sources, and too many move by the undercurrent: mercenary desires and selfish aims drive them; but the good man's driving force falls from above; let him endeavor to prove to all men that this is the most mighty force in existence.