Researches on acoustic space 
21 
that the ratio of the sensitiveness of the right ear to that of the left ear 
was as io to ii. It is probable that the discriminating ability for the 
change in the intensity of a sound depends upon the sensitiveness of the 
ear. As the right ear of the observer was less sharp than the left ear, 
the discriminating ability of the former would be less than that of the lat. 
ter. Accordingly, when the variable soundwas on the left side and the 
constant sound was on the right side the difference between the intensities 
of the two sounds would be more accurately perceived than when the sounds 
were given in the other way. 
Moreover, when the variable sound was on the right side and the con¬ 
stant sound on the left side the observer tended sometimes to localize 
the perceived sound in the rear hemisphere instead of the front, or some¬ 
times he could not decide whether the sound was front or back, though 
he perceived the angular displacement of the sound from o°, for ex¬ 
ample, he could not decide whether the sound came from f or h, fr 6o° 
or fir 6o°. The same uncertainty will be found again in later experi¬ 
ments. The cause of such confusion between front and back location, 
as we may call it, must be sought in the similarity of the relation be¬ 
tween intensities with which the sounds situated in the two directions in 
question are received by the two ears respectively. This point will re¬ 
ceive special consideration later. 
Tabi.k VII. 
Cask I. 
Case II. 
Distance of the 
Distance of the 
secondary coil 
for the left 
Localization. 
Number of 
experiments. 
secondary coil 
for the right 
Localization. 
Number of 
experiments. 
telephone. 
telephone. 
12cm 
br 70° 
I 
I2cra 
/ 90° 
I 
II 
>»■ 52-5 
2 
11 
IO 
br 45 
3 
10 
bl 75 
3 
9 
br 31 
4 
9 
bl 72 
3 
8 
br 10 
3 
8 
bl 20 
3 
7 
b 
i 
7 
br 5 
3 
6.5 
bl 5 
4 
6-5 
br 13 
3 
6 
fit 25 
4 
6 
br 40 
3 
5 
bl 30 
3 
5 
br 66.7 
3 
4 
bl 57 
5 
4 
br 23.3 
3 
3 
bl 50 
3 
3 
br S3.3 
3 
2 
/ 90 
2 
2 
r 90 
3 
i 
l 90 
2 
i 
r 90 
3 
In Case I the probable error varies from In Case II the probable error varies from 
°to±n%. o to ±32%. 
M e must at any rate conclude that the dependence of the localization 
upon the relative difference between the intensities of the impressions