The Pendulograph is a book written by John Andrew, originally published in 1881. The book is a series of writings that explore the twenty ratios of the musical system, also known as sound seen in the silence. The ratios are examined through the use of bi-pendulums, which are pendulums that have two weights instead of one. The book delves into the mathematical and scientific principles behind music and sound, providing a unique perspective on the subject. It is a fascinating read for anyone interested in music theory or the physics of sound. The Pendulograph is a timeless classic that continues to inspire and educate readers today.This scarce antiquarian book is a facsimile reprint of the old original and may contain some imperfections such as library marks and notations. Because we believe this work is culturally important, we have made it available as part of our commitment for protecting, preserving, and promoting the world's literature in affordable, high quality, modern editions, that are true to their original work.