126 Dr. Grecory on the 
3300 Y 
—- =1100 feet, velocity of sound; therm. 35°. 
Same day, half past 12, barom. therm. wind and weather as 
before. Distance between the two bells 1800 feet ; whole distance 
3600 feet. Intervals elapsed in five trials, 3’.25, 3’.24, 3”.26, 3.25, 
3”25; mean 3”.25, 
3600 
35 = 1108 feet, velocity of sound; therm. 35°. 
+(1098 + 1100+ 1108) = 1102 feet, mean velocity from this day’s 
experiments; therm. 35°. 
Friday, May 23. This morning there was a tolerably brisk 
wind blowing from the S.W. by W. nearly in the direction of my 
Charlton’ and Kidbrook stations from Shooter’s Hill. Of this I 
gladly availed myself, as the morning was in other respects 
favourable, in order to ascertain what would be the effect of such 
a wind upon the velocity. Cloudy, air humid, but no rain. 
I measured the velocity of the wind frequently with an ane- 
mometer, and found it vary between 22 and 26 feet, the mean 
24 feet. 
The gun a six pounder, charge 8 oz. of powder. 11, a.m. gun at 
Shooter’s Hill, sound heard at Charlton Lane, distance 6550 feet. 
barom. 29.66 inches. Fahr. therm. 58°, air humid. Sta rounds fired ; 
the intervals were 6’.1, 6’.05, 6”.0, 6”.05, 6”.0, 6’.04; their mean 
6".037. 
= 1085 feet, velocity of sound, when opposed by the wind. 
Same day, quarter past 1, P.M. barom. 29.67 inches, Fahr. therm. 
60°; air dryer. Gun at Charlton Lane. Sound heard at Shooter's 
Hill. Distance 6550 feet. Five rounds fired : the intervals were, 
5".65 doubtful, 5”.8, 5.78, 5”.76, 5".78, omitting the first, the mean 
interval of the other four is 5”.78. 
stitel tee pee 
