( §37 ) ^ 
time after the return of the vibrating Body ; whereupon fome 
fpace muft be left to the fubtil matter, which upon the refilition 
of the Air ftares as from a Center | which aflion being the fame,, 
by the Author fuppofed to be the caufe ofxhcScmd^iB repeated 
upon every vibration. 
But finding ic more difBcult to fhew^how Toms are made by 
a Fipe^ where there are no vifibie vibrations ; he confiders the 
Frame of a Pipe , and the Motion of the Air in if, and thereby 
atcempcs tofiod theCaufeof rheIi?;^^of a Pipe, andthepulfe 
that gives the Soundi not omitting to explicate,how Tlobcs are 
made in Violms^ Harpfecords and Dulcimers, 
To this he fubjoyns an ingenious Difcourfeof the Varyingd^ 
Breaking of Tones, endeavouring to explain, how it is caufed 
both in Strings ^x^dPifes : where occur divers pertinent Obfer- 
vations concerning the motion of Pendulums, the Trumpet Ma^ 
rine^&c the True Trumpet alfo the Sackha, And hanng fliew'd^ 
that Sound doth caufe a motion not only of folid bodies, but of 
the grofTer pares of Air within the Sphere of it ; he confiders, 
that if the Air^which is moved by being inclofed , ftands upon 
fochadegrecofrefiftancetoCompreffionj that ithath aSpring 
vibratmg in the fame meafure with the Sound that puts ic into 
motion, there will be the fame efrea^as when 2 Strings are tuned 
in Unifon;that is,the motion wullbe fo augmented by fucceed- 
ing regular pulfes^that the inclofed Air may be brought to ringi, 
and produce a Tl?»^'. Where he taketh notice of the advice of 
Vitruviud in his Archi£eflure,importing, chat In the ftriiflore of 
^alieatre, there Ihould be vafes or hollow pots of feveral fizes 
to anfwer all the Notes of Mufic1< placed upon the Stage in fiich 
manner, that the voice of j hem which faogupoe the Stage might 
be augmented by the ringingof them : Vuruvimmmnonmgdi- 
vers antient Theaters , where fuch were^ in fome of Ersfi ^ io 
fomeof£4r/^. 
After this, he defcends.to the confideration of the Nature of 
Kep inMufickjand of a fingle Tme ^j which iater^he fairh^con- 
lifts in the facceedingNotes having a due relation to the preced- 
ing,and carrying their proper emphafis by length Joudnefs and 
repetition, with variety that may be agreable to the hearer. 
Next,he treats of Schijmeszwd the Scale of Mufick ; Oiewiog 
that this Scale is not fet out by any determinate quantities of 
whole or half Notes, though the degrees are commonly fo called^ 
but that the degrees in the Mufical Scale are fixed by the Ear in 
rtffc placeSj whei'e thepulfes of the 1^»;?^^ are coincident^ with- 
