ClipArt ETC
"This figure represents the machine endwise, so as to show in what manner the lever operates. The two weights hanging in opposition to each other, the one on the wheel at a, and the other on the axle at b, act in the same manner as if they were conected by the horizontal lever a b, passing from one to the other, having the common centre, c, as a fulcrum between them." -Comstock 1850

Wheel and Axle

"This figure represents the machine endwise, so as to show in what manner the lever operates. The two…