( 41S ) 
The Fourth Mr. Boyle mentions in his Eflay of Lan- 
guid Motion, pa. 14. where he fays, he has more than 
once diligently oblerved, that the Motion of Sound 
pafles above 400 Yards in i". 
The reft of the Numbers are colleded from Experi- 
ments which I tried in feveral Places. When the Fifth 
was tried there was fome Wind ftirring, though not 
much. The Sixth, Seventh and Tenth were tried in a 
clear calm Morning : The Sixth and Seventh were tried 
in Two places in Sr. Johns Grove. 
The Twelfth Experiment was tried Two feveral 
Mornings, the Place where I ftoodwas about 395: Yards 
from the Wall, and the Echo returned in z". The Thir- 
teenth was tried at the Diftance of 213 Yards from the 
fame Wall. And the Fourteenth another Morning at 
ziS Yards Diftance from it ; in each of them the Sound 
was refledted in i". 
The Eighth Experiment was tried in St. John's- Clotjler ; 
and the Fifteenth in Mew-Co/Hege-CloiJieryWhQrG the Sound 
was toffed from one end to another, forward and back 
again feveral times, like that which Merfennus obferved 
at Milan, where he thinks his Voyce was reflefted thus 
at Icaft Ten times, [Reflex^ ch, zo, p. 164.] In St, John's- 
Cloifter, which is 104 Foot and 7 Inches long, I flood 
at one end, and the Sound was repeated 11 times in z\ 
On the North fide of New-CoHege-CloiJler^ which is 1 60 
Foot and 8 Inches long, 1 flood at one end and a Clap was 
repeated 8 times in a little more than 2'' ; I guefs there 
were 7 1 Echoes in 2". From the Number of Echoes here 
in x", I computed the Swiftnefs of the Sound 
Merfennus and the Academy del Cimento conclude. 
That Sounds are all of the fame Quicknefs, whether 
they be great or fmall, and whatever Temper the Air is 
of, though Merfennus was once of another Mind : But 
Kirchert from feveral Experiments, infers, That loud 
Ttt 2 Sounds 
