unate for Trevithick's reputation that his plan died
shortly after this and the project was forgotten.
One project of genuine promise was a tower proposed by the eminent
American engineering firm of Clarke, Reeves & Company to be erected at the
Centennial Exhibition at Philadelphia in 1876. At the time, this firm was
perhaps the leading designer and erector of iron structures in the United
States, having executed such works as the Girard Avenue Bridge over the
Schuylkill at Fairmount Park, and most of New York's early elevated
railway system. The company's proposal (fig. 4) for a 1,000-foot shaft of
wrought-iron columns braced by a continuous web of diagonals was based
upon sound theoretical knowledge and practical experience. Nevertheless,
the natural hesitation that the fair's sponsors apparently felt in the
face of so heroic a scheme could not be overcome, and this project also
remained a vision.
Preparatory Work for the Tower
In the year 1885, the Eiffel firm, which also had an extensive background
of experience in structural engineering, undertook a series of
investigations of tall metallic piers based upon its recent experiences
with several lofty railway viaducts and bridges. The most spectacular of
these was the famous Garabit Viaduct (1880-1884), which carries a railroad
some 400 feet above the valley of the Truyere in southern France. While
the 200-foot height of the viaduct's two greatest piers was not startling
even at that period, the studies proved that piers of far greater height
were entirely feasible in iron construction. This led to the design of a
395-foot pier, which, although never incorporated into a bridge, may be
said to have been the direct basis for the Eiffel Tower.
Preliminary studies for a 300-meter tower were made with the 1889 fair
immediately in mind. With an assurance born of positive knowledge, Eiffel
in June of 1886 approached the Exposition commissioners with the project.
There can be no doubt that only the singular respect with which Eiffel was
regarded not only by his profession but by the entire nation motivated the
Commission to approve a plan which, in the hands of a figure of less
stature, would have been considered grossly impractical.
Between this time and commencement of the Tower's construction at the end
of January 1887, there arose one of the most persistently annoying of the
numerous difficulties, both structural and social, which confronted Eiffel
as the
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