On Musical Duodenes: Or The Theory Of Constructing Instruments With Fixed Tones In Just Or Practically Just Intonation is a book written by Alexander John Ellis in 1874. The book explores the theory and practice of constructing musical instruments with fixed tones in just or practically just intonation. It discusses the use of the duodene, a twelve-note system that is based on the natural harmonic series, and provides instructions for constructing instruments using this system. The book also includes historical information on the development of musical instruments and the use of different tuning systems throughout history. It is a valuable resource for musicians, instrument makers, and anyone interested in the theory and practice of music.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.