e he
expressed his conviction that engineering precedents had nothing to do
with the question of length of span; that it was altogether a money
question. Therefore, since the cheapest method was to be carefully
sought, he determined upon arches,--two abutment piers, two river
piers, and three arches of respectively 502, 520, and 502 feet long.

There were many opponents to this plan; some of them people who would
have opposed any bridge, as, for example, the ferry and the transfer
companies. To his own company he explained away every objection that
came up, as he was bound to do, in view of their confidence in him. He
made the clearest of explanations of the theories involved; and even
such absurd predictions as that his superstructure would crush his huge
stone piers, he took the trouble to blast sarcastically. To an
engineering journal he wrote three letters correcting mistakes in its
accounts of his work. But he seems to have wasted little of his energy
in arguing with the newspaper public. It was a question only of time
till everybody should be convinced.

The most extraordinary care and pains were expended in every direction.
The stone, granite, and steel were both hunted up and tested by
experts, and by machines specially devised in the bridge works, though
not by Eads himself. For his assistants he chose men who were of real
ability and well trained, and to them he invariably gave great credit
for their part in the work. The plans, after being figured out in
detail by them, were gone over by the mathematician Chauvenet, then
chancellor of Washington University, who found not one single error in
them. Most of the big work, such as the masonry and steel, was given
out on contract; and, as was natural, delays by the contractors often
greatly delayed the progress of the bridge. The whole work occupied
seven years.

While Eads had promised the company to prove by careful experiment, so
far as was possible, everything connected with the bridge that had not
already been fully demonstrated in practice, he did not pretend that in
his main outlines he was without some examples. It was in his
development of known ideas and his expedients for simplification that
his genius perhaps most strikingly showed itself. Again and again he
contrived some device so simple that, like a great many strokes of
genius, it seemed that anybody should have thought of it. The massive
piers were sunk to the bed-rock by means of metal caissons