1From Benjamin Franklin to Giambatista Beccaria, 13 July 1762 (Franklin Papers)
...end through the box, on which shank a wheel is fixed by a screw. This wheel serves as a fly to make the motion equable, when the spindle, with the glasses, is turned by the foot like a spinning wheel. My wheel is of mahogany, 18 inches diameter, and pretty thick, so as to conceal near its circumference about 25 lb. of lead. An ivory pin is fixed in the face of this wheel and about 4...