ormly 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.

Practical results have been secured in increasing the distributed
inductance by wrapping fine iron wire over each conductor of the line.
Such a treatment increases the inductance and improves transmission.

The most marked success has come as a result of the studies of
Professor Michael Idvorsky Pupin. He inserts inductances in series
with the wires of the line, so adapting them to the constants of the
circuit that attenuation and distortion are diminished in a gratifying
degree. This method of counteracting the effects of a distributed
capacity by the insertion of localized inductance requires not only
that the requisite total amount of inductance be known, but that the
proper subdivision and spacing of the local portions of that
inductance be known. Professor Pupin's method is described in a paper
entitled "Wave Transmission Over Non-uniform Cables and Long-Distance
Air Lines," read by him at a meeting of the American Institute of
Electrical Engineers in Philadelphia, May 19, 1900.

NOTE. United States Letters Patent were issued to Professor Pupin
on June 19, 1900, upon his practical method of reducing
attenuation of electrical waves. A paper upon "Propagation of
Long Electric Waves" was read by Professor Pupin before the
American Institute of Electrical Engineers on March 22, 1899, and
appears in Vol. 15 of the Transactions of that society. The
student will find these documents useful in his studies on the
subject. He is referred also to "Electrical Papers" and
"Electromagnetic Theory" of Oliver Heaviside.

Professor Pupin likens the transmission of electric waves over
long-distance circuits to the transmission of mechanical waves over a
string. Conceive an ordinary light string to be fixed at one end and
shaken by the hand at the other; waves will pass over the string from
the shaken to the fixed end. Certain reflections will occur from the
fixed end. The amount of energy which