| 14 N. B. S. copper | 240 miles |
| 8 B. W. G. iron | 135 miles |
| 10 B. W. G. iron | 120 miles |
| 12 B. W. G. iron | 90 miles |
| 16 B. & S. cable, copper | 40 miles |
| 19 B. & S. cable, copper | 30 miles |
| 22 B. & S. cable, copper | 20 miles |
+-----------------------------+----------------------+

In 1893, Oliver Heaviside proposed that the inductance of telephone
lines be increased above the amount natural for the inter-axial
spacing, with a view to counteracting the hurtful effects of the
capacity. His meaning was that the increased inductance--a harmful
quality in a circuit not having also a harmfully great capacity--would
act oppositely to the capacity, and if properly chosen and applied,
should decrease or eliminate distortion by making the line's effect on
fundamentals and harmonics more nearly uniform, and as well should
reduce the attenuation by neutralizing the action of the capacity in
dissipating energy.

There are two ways in which inductance might be introduced into a
telephone line. As the capacity whose effects are to be neutralized
is distributed uniformly throughout the line, the counteracting
inductance must also be distributed throughout the line. Mere increase
of distance between two wires of the line very happily acts both to
increase the inductance and to lower the capacity; unhappily for
practical results, the increase of separation to bring the qualities
into useful neutralizing relation is beyond practical limits. The
wires would need to be so far above the earth and so far apart as to
make the arrangement commercially impossible.