430 Prof. J. A. Fleming on the Propagation of 
The above squares were found by a process of trial and 
failure to have inductances which, when used in conjunction 
with the two ebonite condensers in series having a capacity 
of 0:00062 mfd., tuned with the five harmonic oscillations of 
the spiral. 
By the aic of these observations the scale-readings of the 
inductance on the boxwood cylinder were corrected to give 
true values, and these last values have been employed in 
Tables IV., V., and VI. The whole of the observations 
were then repeated, using the ebonite condensers and these 
square wire inductances of predetermined value to form the 
oscillating circuit. The position of the nodes was carefully 
determined by the aid of two neon vacuum-tubes, and the 
results are tabulated in Table VII. 
measured capacity in the condenser circuit. 
The capacity C is the 
The inductance 
L is the calculated value of the square inductance on wire of 
2°03 mm. diameter in the form of a square used. ‘The fre- 
quency 2 is calculated from the values of C and L. The 
wave-length is twice the measured distance between the 
first and second nodes on the helix, and the wave-velocity W 
is the product nA of the calculated frequency and the observed 
wave-length. The wave-length of the tandamental (840 cms.) 
is obtained by dividing the velocity obtained from the 1st 
harmonic by the calculated frequency for the fundamental. 
TaBLE VII.—Inductances and Capacities and Calculated 
Frequencies in the Condenser Circuit required to produce 
the fundamental and Harmonic Oscillations in the long 
Helix. 
Ebonite condenser and square inductances used. 
Oscillation. 
| 
j 
Capacity. |Inductance.| Frequency. 
C. L. 
nN. 
| Fundamental...... 0:0055 56,000 
lst Harmonie...... 0: 00062 56,000 
Peal inet eee i 26,747 
' ord i en as a 15,011 
4th ie a age 9,274 
Sth i eee i 7,470 
028 x10° 
0-847 
1-23 
1-64 
2:08 
2-32 
399 
Wave- 
length. 
X. 
Wave- 
velocity. 
| W=n\X. 
235 x 10° 
235 ,, 
204 ,, 
189° 
183, 
167 cas 
It is seen, therefore, that the velocity obtained from the 
measurements made with the Ist harmonic, viz., 235 x 106 
ems./sec., agrees exactly with that calculated from the in- 
ductance and capacity per unit of length of the helix. On 
