R = Resistance in ohms
L = Inductance in henrys
C = Mutual (shunt) capacity in farads
[omega] = 2[pi]_n_ = 6.2832 times the frequency
S = Shunt leakage in mhos

The quantity _S_ is a measure of the combined direct-current
conductance (reciprocal of insulation resistance) and the apparent
conductance due to dielectric hysteresis.

NOTE. An excellent paper, assisting such study, and of immediate
practical value as helping the understanding of cables and their
reasons, is that of Mr. Frank B. Jewett, presented at the
Thousand Islands Convention of the American Institute of
Electrical Engineers, July 1, 1909.

Chapter 43 treats cables in further detail. They form a most
important part of telephone wire-plant practice, and their uses
are becoming wider and more valuable.

Possible Ways of Improving Transmission. Practical ways of improving
telephone transmission are of two kinds: to improve the lines and to
improve the apparatus. The foregoing shows what are the qualities of
lines and the ways they require to be treated. Apparatus treatment, in
the present state of the art, is addressed largely to the reduction of
losses. Theoretical considerations seem to show, however, that great
advance in apparatus effectiveness still is possible. More powerful
transmitters--and more _faithful_ ones--more sensitive and accurate
receivers, and more efficient translating devices surely are possible.
Discovery may need to intervene, to enable invention to restimulate.