The Speech of Monkeys

Having thus augmented the quantity of sound, by increasing alike the sound unit and interval, it can be recorded on another cylinder and multiplied again as long as the vibrations can produce sound. From the constant relation of parts and their uniform augmentations under this treatment, it has suggested to my mind the idea that all sounds have definite geometrical outlines, and as we change the magnitude without changing the form of the sound, I shall describe this constancy of form by the term contour. In a few instances I have been able, by reducing the record of certain sounds from a high pitch to a lower one, to imitate the sound thus reduced with my own vocal organs, then by restoring this record of my voice to its normal speed have obtained almost a perfect imitation of the sound. This effect, however, does not always follow, and in many instances my best imitations have not developed the original at all. But this presents a new problem in acoustics. I must here take occasion to say that the difference of pitch, quality, &c., in sounds does not appear to me to depend alone upon the length of the sound unit, but there seems to be a difference of ultimate form and mode of propagation which have much to do with the contour of the developed sound. [Sidenote: THE SOUND FORCE]