114- THE HON. J. W. STRUTT ON THE THEORY OE RESONANCE. 
Column 7 contains the values of n estimated by means of the pianoforte, while in 8 is 
given for convenience the discrepancy between the observed and calculated values ex- 
pressed in parts of a mean semitone. ' 
1, 2, 4, 5, 6, 7, 8, 12 were glass flasks with well-defined nearly cylindrical necks, the 
body of the flask being approximately spherical. Of these 1 and 2 had small tubes 
cemented into them, which were inserted in the ear ; the pitch of the rest was estimated 
mainly by their quivering to the resonant note. 3 and 10 were globes intended for 
burning phosphorus in oxygen gas, and their pitch was fixed principally by the help 
of the india-rubber tube passed through the neck. A good ear would find no difficulty 
in identifying the note produced when the body of the globe is struck with the soft part 
of the hand. The agreement is I think very satisfactory, and is certainly better than I 
expected, having regard to the difficulties in the measurements of pitch and of the 
dimensions of the flasks. The average error in Table I. is about a quarter of a semi- 
tone, and the maximum error less than half a semitone. It should be remembered 
that there is no arbitrary constant to be fixed as best suits the observations, but that 
the calculated value of n is entirely determined by the dimensions of the resonator and 
the velocity of sound. If a lower value of the latter than 1123 were admissible, the 
agreement would be considerably improved. 
Table II. 
No. of 
experiment. 
s, 
in cub. centims. 
L, 
in inches. 
cl, 
in inches. 
n, 
by calculation. 
n, 
! by observation. 
Difference, in 
mean semitones. 
9 
1245 
91A 
"16 
14 15 
16? 16 
107-3 
108 
- -11 
11 
216-6 
1 
6 
1 JL5 
4? 16 
526 
538 
- -39 
13 
1245 
1 
1 
163-2 
170 
- -71 
14 
1245 
1 
6 
1 -L& 
4 ? 16 
219-4 
213 
+ -51 
15 
3090 
3 
3 2" 
9-i- 
" J 1 6 
218-1 
227-5 
- -73 
16 
3240 
114 
x 1 6 
is 
4 4 
131-3 
142 
-1-36 
17 
3240 
1 
8 
1J, 1 -K 
± S5 x 1 6 
149-1 
153-5 
- -50 
18 
3240 
5 
1 6 
l-- 5 - 
4 1 6 
153-2 
153-5 
- -03 
19 
3240 
5 
1 6 
1 
129-1 
132 
- -38 
20 
3040 
neglected 
3 2 
48 
128-6 
128 
-f -08 
21 
3240 
H 
1 _i _ 1 _JL_ 
4 1 6 ? 4 32 
101-5 
103-5 
- -34 
22 
3240 
3 
1 6 
Q_7_ 
32 
216 
229 
-1-01 
Table II. contains the results of the comparison between theory and observation for 
a number of resonators whose necks were too short for the convenient measurement of 
the volume. The length and diameter were measured with care and used in formula 
