Musical and harmonic sounds explained--Power of breaking glasses with the voice--Musical sounds from the vibration of a column of air--and of solid bodies--Kaleidophone--Singular acoustic figures produced on sand laid on vibrating plates of glass--and on stretched membranes--Vibration of flat rulers and cylinders of glass--Production of silence from two sounds--Production of darkness from two lights--Explanation of these singular effects--Acoustic automaton--Droz’s bleating sheep--Maillardet’s singing-bird--Vaucanson’s flute-player--His pipe and tabor-player--Baron Kempelen’s talking-engine--Kratzenstein’s speaking-machine--Mr. Willis’s researches. Among the discoveries of modern science, there are few more remarkable than those which relate to the production of harmonic sounds. We are all familiar with the effects of musical instruments, from the deep-toned voice of the organ to the wiry shrill of the Jew’s harp. We sit entranced under their magical influence, whether the ear is charmed with the melody of their sounds, or the heart agitated by the sympathies which they rouse. But though we may admire their external form, and the skill of the artist who constructed them, we never think of inquiring into the cause of such extraordinary combinations. Sounds of all kinds are conveyed to the organ of hearing through the air; and if this element were to be destroyed, all nature would be buried in the deepest silence. Noises of every variety, whether they are musical or discordant, high or low, move through the air of our atmosphere at the surface of the earth with a velocity of 1090 feet in a second, or 765 miles per hour; but in sulphurous acid gas sound moves only through 751 feet in a second, while in hydrogen gas it moves with the great velocity of 3000 feet. Along fluid and solid bodies, its progress is still more rapid. Through water it moves at the rate of 4708 feet in a second, through tin at the rate of 8175 feet, and through iron, glass, and some kinds of wood, at the rate of 18,530 feet.