Velocity of Sound. 127 
6550 
5.78 
z (1085+ 11335) =11094 feet inferred velocity of sound indepen- 
dently of the wind; therm. 59°. 
And (11333 — 1085) =24+ inferred velocity of the wind at the 
times of the experiment, supposing it to be nearly the same at both 
= 11335 feet, velocity of sound, when aided by the wind. 
times. This agrees quite as nearly as could be expected with the 
mean velocity of the wind determined by the anemometer. 
Same day, May 23, half past 11 a.m. barom. 29.67 inches. Fahr. 
therm. 58°: air humid; wind as before. 
Before the gun was removed from Shooter’s Hill, sia rounds 
more were fired. The intervals in which the sound reached Kid- 
brook Lane, were 8".1, 8.125, 8”.13, 8’.15, 8.1, and one very 
doubtful. The mean of these is 8’.121. Distance 8820 feet. 
8820 
8.121 
Here the sound was but just audible, the wind diminishing its 
=1086 feet, velocity of sound, opposed by the wind. 
intensity exceedingly. | 
Same day, therefore, the gun was removed to Kidbrook Lane, 
while I went back to Shooter’s Hill. 
Half past 12, barom. 29.67 inches; Fahr. therm. 60°; air dryer ; 
wind as before. Stax rounds were fired. The intervals between 
the flash and the report were 7’.8, 7.7, 7”.8, 7.78, 7’.78, and one 
very doubtful ; mean 7”.77. 
7 = 1136 feet, velocity of sound, when aided by the wind. 
= (1086+1136)=1113 feet, inferred velocity of the sound inde- 
pendent of the wind ; therm. 59°. 4 (1136—1086)=25 feet inferred 
velocity of the wind, nearly as before. 
The same day, May 23, in the afternoon, the wind subsided, so 
as not to exceed 6 or 8 feet per second, while the temperature of 
the air remained nearly the same. I anxiously availed myself of 
