which had been operating successfully for 10
years. It was the direct plunger system of Leon Edoux, and was, for the
time, far more rationally contrived than Backmann's helicoidal system.
Edoux, an old schoolmate of Eiffel's, had built thousands of elevators in
France and was possibly the country's most successful inventor and
manufacturer in the field. It is likely that he did not attempt to obtain
the contract for the elevator equipment in the Tower legs, as his
experience was based almost entirely on plunger systems, a type, as we
have seen, not readily adaptable to that situation. What is puzzling was
the failure of the Commission's members to recognize sooner Edoux's
obvious ability to provide equipment for the upper run. It may have been
due to their inexplicable confidence in Backmann.

[Illustration: Figure 31.--The French Girard pumps that supplied the Otis
and Roux systems. (From _La Nature_, Oct. 5, 1889, vol. 17, p. 292.)]

The direct plunger elevator was the only type in which European practice
was in advance of American practice at this time. Not until the beginning
of the 20th century, when hydraulic systems were forced into competition
with electrical systems, was the direct plunger elevator improved in
America to the extent of being practically capable of high rises and
speeds. Another reason for its early disfavor in the United States was the
necessity for drilling an expensive plunger well equal in length to the
rise.[14]

As mentioned, the most serious problem confronting Edoux was the extremely
high rise of 525 feet. The Trocadero elevator, then the highest plunger
machine in the world, traveled only about 230 feet. A secondary
difficulty was the esthetic undesirability of permitting a plunger
cylinder to project downward a distance equal to such a rise, which would
have carried it directly into the center of the open area beneath the
first platform (fig. 6). Both problems were met by an ingenious
modification of the basic system. The run was divided into two equal
sections, each of 262 feet, and two cars were used. One operated from the
bottom of the run at the second platform level to an intermediate platform
half-way up, while the other operated from this point to the observation
platform near the top of the Tower. The two sections were of course
parallel, but offset. A central guide, on the Tower's center-line, running
the entire 525 feet served both cars, with shorter guides on either
si