( )

C H A P. X.

Mufick.

■Jftbe Tremhhng .o/ ConsonantStringi ; by Dr.VVallis. n. 13+.

■*•***■"

or

Fig. 221 .

F^J, 222.

Fi$'. 22Z«Fjg; 224 .

Fig. 225 .

I T bath been long since observed, that is a Vial-string, or Lutcßrhg ,be touchcd with ehe Bow or Hand, another String on the sime or a ■nother Instrument not far from it, (it an Vnißn to it, or an OftaVc,tlie libe ) wiil at the sime time Trcmblc os its own accord. But I cannow Add ; that not the \VhoJe os that other St>i>g doth thus Trcmllc, butthe scyeral Parts severally, according as they are Vnifins to the Whole, orthe Parts os that String which is Io ftruk. For Instance, sbpposing AC, tobc an upper Oclavc to a. y, and thcrcsore an Vnißn to each Ha'f os it,stopped at ß. is, w bile ay. is Oper:, AC. be si ruck ; the two Halves ot thisother, that is -r ß, and ßy, will both T rcmllcj but not the \liddle point atß. Which will eaiily be observed, it a little bit os Paper be lighcly wrapcabout the Sning <t >, and removed succeiiively from or.e end os the Stringto the - other.

In like manner, is AD,be an Upper Twelfcb to * =P, and confequentlyan Vnißn to its three parts equally.divided in ß, y; is «A being Opcn, AD.be struck, its three parts a.ß, ßy, y <f, will severally T rcmble, but not thePoints, ß, y. In the like manner, is A E, be' a dcublc OBavc to a«; the fourQuarters os this will Tremble, when that is struck, but no$ the Points ^, y, ASo is AG, be zßlßb tos#; and confequently each Half os that Stopped inDy .an Zhiisan to each Tbird part os t,his stopped in /3, y; whilethat is struck,each part os this will Trcmblc severally, but not the Points ß, y ; and whiiethis is struck, each os that will Trcmblc, but not the- Point D. The like willhold in lesser Concordi ; but the lesi remarkably, as the Number os Divisi-ons encreafes.

This was first os all ( that I know os ) disco vered by Mr. Will. NobleM. A. os Mcrton Colledge ; and by him Ihewed to tome os our Musiciamabout three Years linee 3 and aster him by Mr. Tho. Pigot A. B. of WadbamColledge, withput.hnQWißg.that Jyjg. Nolle hadIdiscoycFd.it before. I add thisfurther ( which 1 took Notice of upon Occasion of making Tryal of the o-ther,) that the fame firing, as -- y, being struck in the midst at ß, ( each partbeing Vnißn to the other) will give no Ciear Sound at ali; but very confused.And not only sb ( which others also have observed, that a String doth notsbund ciear is struck in the midst;) but also is & P, be struck at ß, or y,wbere one part is an OEtavc to the other; and in like manner, is n r, be struck atß, or ^; tbe one part being a double Obi ave to the other. And sb is -tbe struck in y, or </*; the one part being a Fifth to the other; and sb in otherlike Ctmfinant Divisions ; but stili tbe lesi remarkable as the Number of

Divi-

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