consonants are developed from the simple vowel basis, somewhat like chemical compounds result from the union of simple elements. Without describing in detail the results, I shall mention some simple experiments which have given me some very strange phenomena. I dictate to the phonograph a vowel in different keys while the cylinder rotates at a given rate of speed. I then adjust the speed to a certain higher or lower rate and follow the results. By reversing the motion of the cylinder the sounds are reduced to their fundamental state. By this means we eliminate all familiar intonation, and disassociate it from any meaning which will sway the mind, and in this way it can be studied to advantage. [Sidenote: THE SOUND WAVES] At a given rate of speed I have taken the record of certain sounds made by a monkey, and by reducing the rate of speed from two hundred revolutions per minute to forty, it can be seen that I increased the intervals between what is called the sound waves and magnified the wave itself fivefold, at the same time reducing the pitch in like degree, and by this means I could detect the slightest shades of modulation. I may remind you here that in this process all parts of the sound are magnified alike in all directions, so that instead of obtaining five times the length, as it were, of the sound unit or interval, we obtain the cube of five times the normal length of every unit of the sound. The slightest variation of tension in the vocal chords may be detected, and every part of the sound compared to every other part. 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]