636 Onthe Method of judging by thé Ear 
the more, complex one that comprizes the angle 
of elevation, along with: the horizontal distance 
from the axis of hearing. When the sonorous 
object.stands directly in front of the hearer, the 
semicircle ACB may be supposed ‘to \ repre« 
sent the horizontal section of his head, passing 
through the places of the ears, E and F, and 
the axis. of hearing EF; also let G be the 
place of the sounding body, ‘which, according © 
to the conditions of the case, lies. in the: plane 
ACB produced, | and. - likewise' in ‘the right 
line GS, which bisects, EF at right angles: 
seeing. then EF. is bisected by the perpen- 
dicular, SG, the arch ECF is also. bisected 
by the same in the point C,. Draw LG, GK, 
to touch the. circle in T. and P, then will. the 
arcs TEC, and CFP be equal.  Now- all 
the pulses which do not move in right lines, 
contained in the angles TGS and SGP fly 
off without. touching the circle; conséquent- 
ly they add nothing to the sound impressed’on 
the ears by the body placed at G, whether the 
places. E and F be supposed: to lie in the arcs 
TC and CP, or without them. But the 
same number of pulses equal in force will fall 
in a given time, and in similar directions, on 
the arcs TEC and CFP as well as on 
the ears situated at E and F; and it is equally 
manifest, that the same reasoning will apply to 
