ON THE QUALITY OF MUSICAL SOUNDS. 71
no sound intermediate between those given will occur. With the aid of resonators, it will be easy to detect still higher constituents than those mentioned above. It need scarcely be said, that, in the experiments with these instruments, only one reed should be vibrating at a time.
The constituent elements in the compound tones of the voice are more difficult to detect. It is advisable to begin with a good bass voice. All the constituents given above, may be heard after a little practice with the resonators. They are louder in some vowel sounds, as will be seen hereafter, than in others; the "a" sound as in " father," and the " i " as in " pine," are favourable ones to experiment with. After a little practice, the ear becomes practised in this analysis of sounds, and the resonators may be dispensed with to a great extent.
Before proceeding further, it will be best to explain the terms that are used in speaking of these constituents of a compound tone. On one system of nomenclature, the lowest element of a compound tone is termed the Fundamental; the next one (an octave above), the First Overtone; the next (a Fifth above that), the Second Overtone ; the next (a Fourth above that), the Third Overtone; and so on. The constituent elements are also termed Partials ; the lowest being termed the First Partial; the next, the Second Partial; the next, the Third Partial; and so on. Thus, taking (di) as the Fundamental or First Partial, the others will be,
Each of these partials or overtones is a simple tone, that is, a sound of definite pitch, which cannot be resolved into two or more sounds of different pitch. A compound tone is a sound consisting of two or more simple tones.
By means of resonators, many higher partials than the six already mentioned can be detected. The following list contains the first twenty. The first column gives the order of the partials ; the second and third, their names, calling the fundamental C3 and d3 respectively; and the fourth gives the ratios of their vibrational numbers, to the fundamental, this latter being taken as 1.