[ 
( 438 ) 
In Trinity Bdll Courts which is reprerented by Fig. 2. 
when I flood and claptat B, Three or Four Yards from 
the end of the Wall C, or at Ay which is oppofite to 5, 
the Sound was tofled betwixt the oppofite Walls ; but not 
half fo long time as when 1 flood betwixt the Walls. In 
Places where there are parallel Walls, not above Six or 
Eight Yards afunder, as in Trinity BaS-Court, and at the 
Entrarx;e into St fohns-Grove, &c. 1 have heard the 
Echoes of a Clap following one another diftin£Hy enough ; 
but there the Echoes of a Mufical Note, which was Ion- 
ger than a Clap, were fo confufed, that they feemed one 
continued long Sound : which makes me think, that the 
Echo in fome Vauks, is nothing elfe but the Sound tof- 
fed betwixt the Side- Walls, and betwixt the Top and 
Bottom. This alfo makes me conjcfture, that the Rea- 
fon why Stringed Mufical Inflruments give a greater and 
longer Sound to the Strings, than if the Strings were fixt 
to a fingle Board, may be this ; becaufe the Sound is 
tofled from Side to SMe in the Belly of the Inftrumenr. 
1 
m. Further 
