ip6 The 3SQamral Hijlorj 
imprints both figure and motion into it, in the firft Cafe Qer Caf, i. 
Hjp.i. Ffinc. 1.) orelfe communicates its motion only, intheye- 
cond^ {per lUat, 2.) whereby the next undulation of. Air ^ from the 
touched firings taking it juft at its return, and in like manner the 
confequent ones, and moving it as before, they continue their 
vihrntions togtthev ^paJJ?h(^ duquls^ E. P. 
Prop. 2. If tie lefer of tm OSfavesBC^ he touched Fig. 7. 
eacih half of the greater C2, 2D will anfxver it^ the middle 2 
y?i2«i//w^/?/7/^- which he thus demonftrates. 
About CD wraploofly 3 mnowflrips of paper^ one in the middle 
2, the other betwixt C2 and 2P fexemp.gr, in p and q) then with 
t\\Q finger or bow ftrike5G,or any part of it, and you will fee the- 
papers in Z*^, dance and play up and down and about the firing, 
'twixt C2 and 2P, but that in 2 fland flill. Whence it is evident, 
that CD moves in its two halves^ by two diflinU motions. Which 
bethinks occafioned by the arched Airs^ rudiingwith the force of 
BC againft all CD^ and moveing it fomwhat forward out of its 
place ; but finding it of a difproportionate lengthy hignefs^ and 
tenfion^ to be excited by fo quick vibrations^ as may correfpond 
with thofe of BC ^ and the undulations whereinto they ftrikethe 
Air (by which alone it caufes any firing to vibrate) per Illat, 3. 
the fecond undulation of the Air from BC meets CD jufl at its re- 
turn (CD's vibrations to BC's^ and the Airs undulations caufed 
thereby, being as 1 to 2) whereby it is beat back, and rebounds 
from 2 towards BCy whtntheth.i'cd.undulationixomBC occurring, 
forces it forward again ; whereupon fnot being able to move 
backward nor forward) the undulations break and roll away to 
each fide, towards C and D. Which parts ^:2. 2 D helngVnifons 
to BC^ per Princip, 2. it eafily moves them per Prop, i, and fo, 
(though Des Cartes denys it °) they apparently vibrate mp q (vid, 
by two diftin^ motions, D. 
Prop. 3 . If the greater of two Odiaves QX> be toucht on either of 
its halves C2. 2D. all the lejferwill anfrer it, but if on the 
middle 2 it will Jiir no wh^re. Which is thus demonftrated. 
About BC, Fig. J. wrap loofly one Jlrip of paper, then with the 
finger or how^ ftrike CD on either half C2 or 2 and you will fee 
" D.'s Cartes Muf.Cmp- p-<j. 
the 
