arsh, and some sandy
soil bearing willows. At the sea end of South Pass Eads extended the
low banks out over the bar, by driving rows of guide-piles and sinking
willow mattresses close alongside them on the riverside. The mattresses
were sunk in tiers, and each tier was weighted well with rock, put in
as soon as each mattress was in position. As usual he invented many of
the requisite mechanical appliances and contrivances himself, and
generally such good ones that his methods came to take the place of
earlier ones. The South Pass was not only the smallest and shallowest
of the mouths, but it was besides more difficult than the other two in
having a bar at its head as well as at its sea end. And although by his
contract Eads was not required to remove that bar, by the exigencies of
the case he was. Like the other it had to be attacked with water,
guided by dikes and dams, which were similar in construction to the two
parallel banks, the jetties proper. The scheme was always to force the
river itself to do all the real work; and though there was, to be sure,
a good deal of planning and building, the main idea, as already
explained, is exceedingly simple. Eads never pretended to have
originated this idea. He had studied many jetties in Europe. He had had
the eye to see that they could be adapted to the Mississippi, and the
skill to adapt them. For simple as the bald theory is, there was need
of the nicest appreciation of laws and forces in applying it, and the
result has been called the greatest engineering feat ever accomplished.
The problem of making the quantity of water needed run _up_ into the
smallest pass "through a narrow, artificially contracted channel,
located immediately between two great natural outlets,"--this problem
being complicated by many "occult conditions,"--has been called, by no
mean engineer, perhaps the most difficult problem ever dealt with
successfully. "There is no instance, indeed, in the world where such a
vast volume of water is placed under such absolute and permanent
control of the engineer, through methods so economic and simple."

To the non-mechanical mind the control of such a multitude of abstruse,
minute, and exact details as combine in the making of a bridge seems
perhaps more marvelous than the mere bending of nature's forces to
serve the ends of man. In Eads the power to do both existed.

On piles in the marsh houses were built for the engineers and the
workmen, and the Jetties w