92 IOWA ACADEMY OF SCIENCE Voi,. XXVIII, 1921 
TABLE I 
Frequency 
E 
s 
Log S 
(ergs) 
11,500 
.65 X 10-7 
1.54 X 107 
7.19 
12,800 
1.66 X 10-7 
6.00 X 106 
6.78 
13,300 
3.14 X 10-7 
3.17 X 106 
6.50 
13,900 
5.66 X 10-7 
1.77 X 106 
6.25 
14,500 
2.77 X 10-6 
3.61 X 105 
5.56 
15,000 
3.60 X 10-6 
2.38 X 105 
5.38 
15,700 
5.80 X 10-6 
1.72 X 105 
S.23 
16,200 
2.05 X 10-5 
4.87 X 104 
4.69 
16,800 
2.00 X 10-4 
5.00 X 103 
3.70 
These results, while only for one observer, are significant. They 
show that near the upper limit of audition the sensitivity of the 
ear falls off very rapidly for an increase in frequency beyond a 
certain limit. It was not found possible to produce sound of sufficient 
intensity at a frequency of 17,000 for audition for the observer 
from whom these results were obtained. 
Physics Department 
State University oe Iowa 
