one on the
same spot, and yet the traffic in the meantime must not be disturbed in
the least. It would seem that this was impossible, but the engineers
intrusted with the work undertook it with perfect confidence. To any one
who has seen the rushing, roaring, foaming waters of unknown depth that
race so fast from the spray-veiled falls that they are heaped up in the
middle, the mere thought of men handling huge girders of steel above the
torrent, and of standing on frail swinging platforms two hundred or more
feet above the rapids, causes chills to run down the spine; yet the work
was undertaken without the slightest doubt of its successful fulfilment.

It was manifestly impossible to support the new structure from below,
and the old bridge was carrying about all it could stand, so it was
necessary to build the new arch, without support from underneath, over
the foaming water of the Niagara rapids two hundred feet below. Steel
towers were built on either side of the gorge, and on them was laid the
platform of the bridge from the towers nearest to the water around and
under the old structure. The upper works were carried to the solid
ground on a level with the rim of the gorge and there securely anchored
with steel rods and chains held in masonry. Then from either side the
arch was built plate by plate from above, the heavy sheets of steel
being handled from a traveller or derrick that was pushed out farther
and farther over the stream as fast as the upper platform was completed.
The great mass of metal on both sides of the Niagara hung over the
stream, and was only held from toppling over by the rods and chains
solidly anchored on shore. Gradually the two ends of the uncompleted
arch approached each other, the amount of work on each part being
exactly equal, until but a small space was left between. The work was so
carefully planned and exactly executed that the two completed halves of
the arch did not meet, but when all was in readiness the chains on each
side, bearing as they did the weight of more than 1,000,000 pounds, were
lengthened just enough, and the two ends came together, clasping hands
over the great gorge. Soon the tracks were laid, and the new bridge took
up the work of the old, and then, piece by piece, the old suspension
bridge, the first of its kind, was demolished and taken away.

Over the Niagara gorge also was built one of the first cantilever
bridges ever constructed. To uphold it, two towers were