122 Dr. Grecory on the 
to confide. With regard to the distances between the stations at 
which the sound was emitted and heard, they were in some cases 
taken from the Ordnance Map of Kent, and verified by new ope- 
rations; in others they were determined by actual and careful 
measurement: in others by trigonometrical operations with accurate 
instruments. The whole were conducted with care; and it would 
be useless to enter into the detail of them. 
Fripay, January 3, 1823. 
A musquet was fired from the battery near the Royal Artillery 
Barracks, and the interval of time between the flash and sound 
was observed at two different distances on the mortar-range, di- 
rection nearly north and south. 
January 3, half past 2, P.M. barom. 29.7 inches, Fahr. therm. 45°, 
rather moist atmosphere, but no rain; very gentle wind blowing 
in direction nearly perpendicular to that of the range. 
Distance from musquet to my station 3600 feet. Sta rounds 
fired: in one the interval of time employed by the sound in 
passing over the 3600 feet was doubtful: in the other five the 
intervals were 3”.25, 3”.3, 3'2.5,, 3.2, 3”.26, the mean of these is 
BOE 
3600 
3.252 
Same day, three o’clock p.m. barom. 29.64 inches, Fahr. therm. 
45°. atmosphere, wind and weather as before. 
Distance from musquet to station 3600 feet. Five rounds fired, 
intervals, 3”.2, 3”.2, 3.3, 3”.3, 3’.25; their mean 3”.25. 
3600 : 
Spr As feet, velocity of sound; therm. 45°. 
=1107 feet, velocity of sound; therm. 45°. 
Same day, half past 3, p.m. barom. 29.64 inches, Fahr. therm. 45’. 
atmosphere, wind, and weather, as before. 
Distance from musquet to station 2100 feet. Eight rounds fired 
EE 
