VOL. XII.] PHILOSOPHICAL TRANSACTIONS. 381 



divided in p, y. Now if, a$ being open, AD be struck, its three parts, a(3, |3y, 

 y$, will severally tremble, but not the points p, y ; which may be observed in 

 like manner as the former. In like manner, if AE (fig. 9) be a double octave 

 to at; the four quarters of this will tremble, when that is struck, but not the 

 points (3, y, S. So if AG be a fifth to an, (fig. 10) ; and consequently each half 

 of that stopped in D, an unison to each third part of this stopped in yt, while 

 that is struck, each part of this will tremble severally, but not the points y, t ; 

 and while this is struck, each of that will tremble, but not the point D. The 

 like will hold in less concords, but the less remarkably as the number of divi- 

 sions increases. 



This was first of all, that I know of, discovered by Mr. William Noble, a 

 Master of Arts of Merton College, and by him showed to some of our musicians 

 about three years since; and after him by Mr. Thomas Pigot, a Bachelor of 

 Arts, and Fellow of Wadham College; who giving notice of it to some others, 

 found that, unknown to him, the same had been formerly noticed by Mr. 

 Noble, and upon notice from him, by others; and it is now commonly known 

 to our musicians here. I add this further, which I took notice of on occasion 

 of making trial of the other, that the same string as xy, being struck in the 

 midst at (3, each part being unison to the other, will give no clear sound at all, 

 but very confused. And not only so, which others also have observed, that a 

 string does not sound clear if struck in the middle, but also, if x$ be struck at 

 |3 or y, where one part is an octave to the other; and in like manner, if « t be 

 struck at (3 or <?; the one part being a double octave to the other. And so if a^ 

 be struck in y or S, (fig. 11 ) the one part being a fifth to the other, and so in 

 other like consonant divisions; but still the less remarkable as the number of 

 divisions increases. This and the former I judge to depend upon one and the 

 same cause, viz. the contemporary vibrations of the several unison parts, which 

 make the one tremble at the motion of the other ; but when struck at the res- 

 pective points of divisions, the sound is incongruous, by reason that the point 

 is disturbed which should be at rest. 



A lute or viol-string will thus answer, not only to a consonant string on the 

 same or a neighbouring lute or viol, but to a consonant note in wind-instru- 

 ments, which was particularly tried on a viol, answering to the consonant notes 

 on a chamber-organ, very remarkably, but not so remarkably to the wire -strings 

 of a harpsichord. Which, whether it were because of the different texture in 

 metal-strings from that of gut-strings, or, which I rather think, because the 

 metal-strings, though they give to the air as smart a stroke, yet not so diffusive 

 as the other, I list not to dispute. But wind-instruments give to the air as 

 communicative a concussion, if not more, than that of gut-strings. And we 



