About 1738, a merchant of Cleves, named Jorissen, who had become almost totally deaf, sitting one day near a harpsichord, while some one was playing—and having a tobacco-pipe in his mouth, the bowl of which rested accidentally against the body of the instrument—was surprised to hear all the notes most distinctly. By a little reflection and practice, he again attained the use of this valuable sense; for he soon learned—by means of a piece of hard wood, one end of which he placed against his teeth, while another person placed the other end on his teeth—to keep up a conversation, and to be able to understand the least whisper. The effect thus described is the same, if the person who speaks rests his stick against his throat or his breast; or when one rests the stick which he holds in his teeth against some vessel into which the other speaks.