[Illustration: Figure 37.--Schematic diagram of the Edoux system. (Adapted from Gustave Eiffel, _La Tour de Trois Cents Mètres_, Paris, 1900, p. 175.)] [Illustration: Figure 38.--Vertical section through lower (suspended) Edoux car, showing Backmann helicoidal safety brake. (Adapted from Gustave Eiffel, _La Tour Eiffel en 1900_, Paris, 1902, p. 12.)] A curiosity in connection with the Edoux system was the use of Worthington (American) pumps (fig. 40) to carry the water exhausted from the cylinders back to the supply tanks. No record has been found that might explain why this particular exception was made to the "foreign materials" stipulation. This exception is even more strange in view of Otis' futile request for the same pumps and the fact that any number of native machines must have been available. It is possible that Edoux's personal influence was sufficient to overcome the authority of the regulation. [Illustration: Figure 39.--Passengers changing cars on Edoux elevator at intermediate platform. (From _La Nature_, May 4, 1889, vol. 17, p. 361.)] [Illustration: Figure 40.--Worthington tandem compound steam pumps, at base of the Tower's south pier, supplied water for the Edoux system. The tank was at 896 feet, but suction was taken from the top of the cylinders at 643 feet; therefore, the pumps worked against a head of only about 250 feet. (From _La Nature_, Oct. 5, 1889, vol. 17, p. 293.)] [Illustration: Figure 41.--Recent view of lower car of the Edoux system, showing slotted cylindrical guides that enclose the cables.] Epilogue In 1900, after the customary 11-year period, Paris again prepared for an international exposition, about 5 years too early to take advantage of the great progress made by the electric elevator. When the Roux machines, the weakest element in the Eiffel Tower system, were replaced at this time, it was by other hydraulics. Built by the well known French engineering organization of Fives-Lilles, the new machines were the ultimate in power, control, and general excellence of operation. As in the Otis system, the cars ran all the way to the second platform.