TUNE, or TONE, in music, is that pro perty of sounds by which they come un der the relation of acute and grave. If two or more sounds be compared to gether in this relation, they are either equal or unequal in the degree of tune; such asnre equal, are called unisons ; the unequal constitute what are called inter. vals, which are the differences of tone between sounds. Sonorous bodies are found to differ in tone : 1st. According to the different kinds of matter : thus the sound of a piece of gold is much graver than that of a piece of sliver of the same shape and dimensions. 2d. According to the different quantities of the same mat ter in bodies of the same figure ; as a solid sphere of brass, of one foot fliaMe ter, sounds acute r than a sphere of brass of two feet diameter. But the of tone are only to be-sought in the rela tions of the motions that are the cause of sound, which are.most discernible in the
vibration of chords. Now, in general, we find that in two chords, all things being equal excepting the tension, the f Iiickness, or the length, the tones are different; which difference can only be in (lie veloci ty of their vibratory motions, by which they perform a different numiker Of6ibratio4s in the same time ; as it iJ known that all the small vibrations of the same chord are performed in equal times. low the frequenter or quicker those iftrations are, the more acute is the tonj; and the slower and fewer they are in the same space of time, by so much thtt more grave is the tone. So that any given note of a tune is made by one certain measure of velocity of vibrations, that is, such a cer tain number of vibrations of a chord Or string, in such a certain, space of time, constitute a determinate tone.