he arches. The tubes were found to be two and a half
inches too long to go in, although they would be only the required
length when they were in. It was left for Eads to insert them.
Shortening them would of course have lowered the arch. Eads, who was
just starting for London on financial business of the bridge, cut the
tubes in half, joining them by a plug with a right and left screw. Then
he cut off their ends, for the plug would make them any required length
by inserting or withdrawing the screws a little. Then he went away. As
it would have been much cheaper not to use this device, his assistants
tried for hours to shrink the tubing by ice applications, and thus to
get the arches closed; and there is a popular tradition in Saint Louis
that they succeeded; but it was excessively hot weather, and they did
not succeed. The screw-plug tubes, of course, were easily put in. Any
part of this steel work can be at any time safely removed and
replaced,--another structural feature original in this bridge.

Although Eads took care to protect his special innovations by patent,
he was most willing to explain them with care to other engineers and to
have others profit by his improvements; and several of the mechanical
novelties of his bridge are now in the commonest use, and have been
taken advantage of even in such famous structures as the Brooklyn
Bridge.

During the building of the bridge Eads spent many months in enforced
absence, but while in Europe he always had his labor in mind, and, as I
have said, brought home from France one of his most useful appliances.
During his absence he left absolutely trustworthy and efficient
engineers in charge of the work, and before leaving home he provided
for accidents that might occur. So much work was done in the winter
that great barriers had to be built to keep it clear of floating ice.
One curious detail connected with the bridge is that the Milwaukee, one
of the double-turreted gunboats which Eads had built from his own
plans, and which had been with Farragut at Mobile, was bought now from
a wrecking company, and her iron hull used in making the caissons; so
that her usefulness still continued in peace as in war.

It has been said of Eads that he grappled with great problems in
engineering, and solved them as easily as a boy subtracts two from six.
While this is true, it must not be forgotten that he had not the
school-training of an engineer. Nothing is more untrue than the
state