THE BROOKLYN BRIDGE. 387 



then bent over it, and the socket is filled up with melted lead. Each 

 suspender is tested to sustain 100 tons, but the greatest weight that 

 can come upon any one is 10 tons. 



Besides being suspended in this way from the cables, the spans are 

 further secured for 437 feet each way from the towers by stay-ropes, 

 27 of which start from each saddle-plate, and, spreading out like the 

 sticks of a fan, are attached, at intervals of 15 feet, to the bottom 

 chords of the trusses. 



There are six vertical trusses which inclose the five ways into 

 which the roadway is divided. The top chords of the two outer trusses 

 are 9j feet above the roadway, those of the other four are 16 feet. 

 Each truss has a slip-joint in the middle of each span to allow for ex- 

 pansion and contraction of the structure from heat and cold. For a 

 hundred feet out from the towers these trusses are said to be able 

 to support themselves, not adding their weight to the strain on the 

 cables. 



The floor-beams, which lie crosswise, at intervals of 7 feet, are 

 86 feet long, and each consists of two sections spliced end to end. 

 To each beam are attached four suspenders, one from each cable, 

 except for 250 feet out from the anchorages, where the cables dip 

 below the roadway, the floor-beams resting on pillars above them, 

 and in the archways of the towers, where the beams rest upon the 

 masonry. The beams are triangular lattice-girders, having a top and 

 a bottom chord connected by vertical posts and diagonal braces. They 

 are 32 inches wide and 9 inches thick. Alternating with these main 

 floor-beams are lighter beams which are fastened to them by cross- 

 ties. 



The three spans are protected ^against lateral swaying by four 

 stays from each corner of each tower, which run out just under the 

 roadway, and are attached to the truss at the opposite side at different 

 distances. Beyond these are other similar stays running from side to 

 side. Further, the two outer cables are drawn inward, and the two 

 inner ones outward, as they recede from the towers, so that each op- 

 poses its weight in the form of an arch to lateral movement. The sus- 

 penders also tend to prevent swaying, for, instead of descending verti- 

 cally, each is drawn in toward its half of the bridge. 



The total length of the bridge and approaches is over a mile and 

 an eighth (5,989 feet). The middle of the main span is 135 feet above 

 high- water mark, at 90 Fahr. This is sufficient for the bulk of the 

 shipping that uses the East River, but the largest ships have to take 

 down their highest spars to clear it. The cable-wire, trusses, and floor- 

 beams are all of steel, this being the first steel suspension-bridge ever 

 built. The total weight of the suspended portion, including the cables, 

 is 14,680 tons, and the total load that can come upon it is 3,100 tons. 

 To support these 17,780 tons we have the cables, with a united strength 

 of 54,244 tons, and in addition the trusses and stays, which bear no 



