314 MB M O IR S of the 
but as oblique as the line Fig. 5. Plate IX. A B is to the 
line B C, where A reprefents the gare, B C the Sail-court wall, 
and B D another wall ^ or if you ftand at E the corner of the 
grove next to ^I'rinity\ and clap, the eccho will return to you from 
the 'BallCourtj in the fame grove he flood about 20 yards from 
the fame crate, and the gate being fliut he clapt and at other times 
ftamped, and the eccho returned from the gate as loud, if not 
louder than the clap or flamp ; an eccho refleded from a gate or 
door has ufually a bafer and duller found than that which is re- 
turned from a wall, this being much brifker : As he has been 
walking towards a wall he clapped his hands together feveral 
times, and could diftinguiflithe eccho from the clap, till he came 
within 7 or 8 yards of the wall ^ in the cloiflers where the eccho 
was repeated feveral times, the iirft repetition feemed to be flower 
than the fecond or third, but of all the repetitions befides the 
firft, the fubfequent feemed flower than the precedent 5 he ob- 
Icrved the toffing of a found forward and back again in very 
many places where there are parallel walls 5 and where the dil- 
france of the wall is lels, there the ecchoes follow one another 
quicker 5 wherelbever a found was thus toffed betwixt two walls, 
if he rtood about the middle, he could hear the found twice as 
quick, that is twice as often repeated in one fecond, as if he 
ftood near one wall, the found being refle^ied to him from both 
ends, when he ftood in the middle : In Trinity Sail-court^ when 
he flood and clapt Fig. 6. at B, three or four yards from the end 
<:f the wall C, or at A which is oppofite to B, the found was tof 
fed betwixt the oppofite walls, but not half fo long as when he 
ftcod exaftly betwixt the walls ^ in places where there are pa- 
rallel walls not above 6 or 8 yards alijnder, as in Trinity Sail- 
court and at the entrance into St. Johnh Grove^ Sic. he heard the 
ecchoes of a clap following one another diftinflly enough ^ but 
there the ecchoes of a mufical note which was longer than a clap, 
were lo confufed that they leemed one continued long found, 
which made him think that the eccho in fome vaults is nothing 
ehe, but the found tofled betwixt the fide walls and betwixt the 
top and bottom^ this alio made him conjc<^ure that the reafon 
why ftringed inftruments give a grcatet and longer Ibund to the 
ftrings, than if the Itrings were fixt to a fingle board, may be 
this I becaufe the found is tofled from fide to fide in the belly of 
the inftrument. 
^^l 
