THE KANSAS CITY BRIDGE.

moored on the south side of the works, by which the stones were lifted from the
stone barges and placed on the car ; the car was then pushed under one of the
travellers, the stone raised by a hand-crab which was placed at the east end of
the works till it cleared the car, and drawn forward till opposite the desired
point by a steam crab, which was likewise at the east end of the works, and
driven by the same engine which worked the dredges, both sets of machinery
rarely being worked together. This apparatus was not mounted till the beton
in the two lower sections of the caisson had all been put in.

Soon after the caisson was brought into position the rectangular openings
into the lower chambers had been surmounted by timber boxes ; this was con-
tinued from time to time as the sinking progressed, the successive sections of
these well walls being made of such height as was found most convenient. When
the hollow walls of the caisson had been filled with beton a second section was
built above it; this section was an open frame structure, covered with three-
inch oak plank dressed in a planer, and similar to the caissons used at Piers 1
and 3; the long sides were given a batter of one in sixteen, but the short sides
of the starlings were built plumb ; additional lengths were also put on.the gas
pipes. This section, like the lower one, was filled with beton, about one-half
the full amount being put in before starting the machinery. The beton was
mixed upon the platform, thrown at once into the caisson, and beaten down with
a paving maul. It set rapidly, forming a satisfactory compound; the caisson
thus became merely the wooden covering of a single artificial stone or monolith,
of the form most convenient for the work, and which carried the masonry of
the pier above. |

» On the 11th of December the ice closed at the bridge line, and the river
froze across. A week later the ice, which was still thin, began to rot rapidly
under a strong sun, and on the 19th it broke up and went out. No serious
damage was done, but a large sheet of ice, jamming above the draw rest, forced
inwards the ice along the north shore, which, swinging on a pivot, about the
anchor piles above the works, tore out two piles on the north-west corner of
the false-works of this pier, the injury being done at one of those points where
the exposure was supposed to be least. The damage was soon repaired ; one of
the piles had only been bent over, and was drawn back into place ; the other,