longitudinal and cross girders being the same, so as to permit of making the longitudinal girders continuous by means of cover-plates. To permit of the use of similar cover-plates for the bottom flanges of the longitudinal girders, the webs of the cross-girders are to be slotted for their passage, and the weakened web sections are to be strengthened by means of angle-irons.

The cross-girders, which are slightly fish-bellied, are to be riveted at their ends into hangers, each of which is composed of two twelve-inch I beams, the distance between the vertical axes of hangers being forty-one feet. Beyond the hangers will be cantilever brackets for carrying the highway stringers, said brackets being connected at top to the cross-girders by cover-plates and at the bottom by planed ends that will afford effective contact for the meeting flanges.

At the top of each hanger is a detail for connecting to the cables, and beneath the same is placed a hydraulic buffer so arranged that, when the movable deck is at its lowest position, the live load thereon is carried by the hangers through the buffers to certain cantilever brackets, which project from the ends of the cross-girders of the supporting span.

These cantilever brackets and the fish-bellying of floorbeams and stringers are the only peculiar features of the supporting span, with the exception of the vertical end posts and the unusual sizes of all truss members.

While the live load of the movable deck is carried through the hydraulic buffers to the bottom of the supporting span, the dead load passes by means of the wire cables to the top of said span.

The lifting deck will be operated by electrical machinery located in the house at the middle of the top of the through or supporting span. The weight of the lifting deck, which amounts to about 1,850,000 pounds, is counterbalanced by cast iron weights in groups, each about four feet long, four feet wide, and four feet six inches high, strung on tightly adjusted rods to hold them in position ; and is supported by one hundred and twelve steel-wire cables one and a quarter inches in diameter  that  pass  over  fifty-six  cast-iron  sheaves  five  feet  in