Some two hundred and fifty years ago someone noticed that bell ringers attained a remarkable muscular development of the chest, shoulders, and arms, thanks to repeated exercise in pulling the ropes which put the great weight of the bells in motion.
Whoever the person was, he figured out a scheme for erecting a device which would simulate the bell ringer’s gallery, but without the bells.
This device could be installed in the corner of a room or in the attic. The English essayist, Joseph Addison, had one in his room.
The rope was probably attached to weights suspended over a pulley from the ceiling. A wooden bar, knobbed at the ends to keep the hands from slipping, was knotted to the other end of the rope and hung just within the reach of the exerciser.
He could thus duplicate the physical activity of the bell ringer and, by regulating the weight, get whatever degree of exercise he might wish. Because there was no bell attached to this apparatus, it became known as a dumb bell.
Later on someone else discovered that one could get much the same kind of exercise by dispensing with most of the cumbersome contrivance, using only the wooden bar or a heavier one of metal. This simpler device, because originally a part of the earlier equipment, continued to be known as dumbbell, though no longer associated otherwise with the art of bell ringing.
The modern dumbbell of American slang does not get its meaning from either of the above devices, other than by a play upon words. It was applied originally only to females, to the belle of the beautiful-but-dumb type.