and on Reed Organ-Pipes. 249 



and similarly, if the secondary interval were taken = a + 2w+T.s, 

 we ought to have the same on both sides of d, J] &c. The 

 pulsations in each of these groups, however, are either all con- 

 densed or all rarefied. Near b, therefore, they will tend to 

 coalesce, and will scarcely be sufficiently distinguished from 

 each other to impart the vowel quality in the same way that 

 groups of alternate pulsations do. AVhen they suggest any musical 

 note at all, it will plainly be an octave higher than if the 

 pulsations were alternate, because in the latter case, the interval 

 between one condensed pulse and another, is twice that in the 

 former. As the vowels have been shewn to be identified by the 

 musical note of the secondary groups, it follows, therefore, that 

 each vowel will, in this new series, be at twii.e the distance from 

 b, d, &c. that it is in the original series from a, c, e, &c. I have 

 already mentioned, that vowels of this kind are to be found 

 on both sides of these points, b, d, &c. (See No. 4.) 



Having shewn the probability that a given vowel is merely 

 the rapid repetition of its peculiar note, it should follow that if 

 we can produce this rapid repetition in any other way, we may 

 expect to hear vowels. Robison and others had shewn that a 

 quill held against a revolving toothed wheel, would produce a 

 musical note by the rapid equidistant repetition of the snaps of 

 the quill upon the teeth. For the quill I substituted a piece 

 of watch-spring pressed lightly against the teeth of the wheel, 

 so that each snap became the musical note of the spring. The 

 spring being at the same time grasped in a pair of pincers, so 

 as to admit of any alteration in length of the vibrating portion. 

 This system evidently produces a compound sound similar to 

 that of the pipe and reed, and an alteration in the length of 

 the spring ought therefore to produce the same eiFect as that of 

 the pipe. In effect the sound produced retains the same pitch 

 as long as the wheel revolves uniformly, but puts on in succes- 



Vol. 111. Piirt I. il 



