existing width of waterway in the river itself, which is sometimes
subjected to heavy floods.

These considerations evidently precluded the construction of a central
pier and double-armed swing bridge, and on the other hand they also
precluded the construction of any solid masonry substructure for the
turntable, either upon the quay or projected into the river. To meet
these several conditions the bridge has been designed in the form of a
three-span bridge, that is to say, it is only supported by the two
abutments and two intermediate piers, each consisting of a pair of
cast-iron cylinders or columns, as shown by the dotted circles upon the
general plan.

The central opening is that which serves for the passage of vessels. The
swing bridge extends over two openings, or from the north abutment to
the southern pier, its center of revolution being situated over the
center of the northern span, and revolves upon a turntable, which is
carried upon a lower platform or frame of girders extending across the
northern span of the bridge. The southern opening is spanned by an
ordinary pair of lattice girders in line with the girders and
superstructure of the swing bridge.

We propose at an early date to publish further details of this bridge,
and the hydraulic machinery by which it is worked.

We present a perspective view of the bridge as seen from the entrance to
the exhibition building, which is situated in close proximity to the
southern end of the bridge.--_Engineering_.

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