r protracted fighting, was sustained by Judge
Green in 1893, the Electrical Engineer remarked that the General
Electric Company "must certainly feel elated" because of its importance;
and the journal expressed its fear that although the specifications and
claims related only to the maintenance of uniform pressure of current on
lighting circuits, the owners might naturally seek to apply it also to
feeders used in the electric-railway work already so extensive. At this
time, however, the patent had only about a year of life left, owing
to the expiration of the corresponding English patent. The fact that
thirteen years had elapsed gives a vivid idea of the ordeal involved in
sustaining a patent and the injustice to the inventor, while there is
obviously hardship to those who cannot tell from any decision of the
court whether they are infringing or not. It is interesting to note that
the preparation for hearing this case in New Jersey was accompanied by
models to show the court exactly the method and its economy, as
worked out in comparison with what is known as the "tree system"
of circuits--the older alternative way of doing it. As a basis of
comparison, a district of thirty-six city blocks in the form of a square
was assumed. The power station was placed at the centre of the square;
each block had sixteen consumers using fifteen lights each. Conductors
were run from the station to supply each of the four quarters of the
district with light. In one example the "feeder" system was used; in
the other the "tree." With these models were shown two cubes which
represented one one-hundredth of the actual quantity of copper required
for each quarter of the district by the two-wire tree system as compared
with the feeder system under like conditions. The total weight of copper
for the four quarter districts by the tree system was 803,250 pounds,
but when the feeder system was used it was only 128,739 pounds! This
was a reduction from $23.24 per lamp for copper to $3.72 per lamp. Other
models emphasized this extraordinary contrast. At the time Edison was
doing this work on economizing in conductors, much of the criticism
against him was based on the assumed extravagant use of copper implied
in the obvious "tree" system, and it was very naturally said that there
was not enough copper in the world to supply his demands. It is true
that the modern electrical arts have been a great stimulator of copper
production, now taking a quarter of