Note 218 — Chapter XIV

An instrument designed to reinforce these upper tones, so that they may be clearly heard, is to be found in any Physical Laboratory. That these tones really vibrate "sympathetically" may be proved by striking ff this note and then pressing down very lightly the keys of G and E just above middle C, thus removing the individual dampers of these notes. In a quiet room the tones are distinctly audible. For another rewarding experiment of the same nature, see the Introduction to the first volume of Arthur Whiting's Pedal Studies and the well-known treatise of Helmholtz.