6 
ME. E. J. STONE ON THE VELOCITY OF SOUND. 
N 
0 is the position of the observer at the Observatory. 
K is the position of the observer near the gun G. 
F indicates the direction of the gun. 
N, N point north. 
G 0 = 15449 feet; GK= 640-5 feet. 
Angle OGK=36° 48'; GON=76° 2'. 
