Table of contents : On the sensation of sound in general -- On the composition of vibrations -- Analysis of musical tones by sympathetic resonance -- On the analysis of musical tones by the ear -- On the differences in the quality of musical tones -- On the apprehension of qualities of tone -- Combinational tones -- On the beats of simple tones -- Depth and deepest tones -- Beats of the upper partial tones -- Beats due to combinational tones -- Chords -- General view of the different principles of musical style in the development of music -- The tonality of homophonic music -- The consonant chords of the tonal modes -- The system of keys -- Of discords -- Laws of progression of parts -- Esthetical relations.