596 PROCEEDINGS OP SECTION J. 



on January 31st., 1881. Iron Cove Bridge, drawings of which 

 were completed in 1887, is of the same general design, but without 

 swing, and consists of nine spans of one hundred and twenty -six feet 

 three inches, on four feet six inches diameter cylinders. Opened 

 for traffic in 1882. 



Nowra Bridge, designed in 1879, consists of eight American 

 (double intersection Murphy-Whipple) truss spans ; one, one 

 hundred and eighty-three feet nine and a-half inches ; one, one 

 hundred and twenty- six feet ten and a-half inches ; four, one 

 hundred and twenty-six feet four inches ; and one, one hundred 

 and twenty-five feet two and a-half inches, also one span of fifty 

 feet ordinary plate girders. The piers are formed of cast-iron 

 cylinders seven feet and five feet diameter, braced with horizontal 

 and diagonal bracing. Depth between centres of top and bottom 

 members of trusses, twenty-five feet ; width between centres of 

 trusses, twenty-two feet six inches ; clear width of roadway 

 between curbs, nineteen feet eleven and a-half inches. The bridge 

 rests at its northern end upon an abutment of freestone masonry, 

 and was opened for traffic on August 1, 1881. 



The Manilla Bridge, over the Namoi River was designed in 

 1881. The main spans consist of five non-continuous wrought- 

 iron lattice girders one hundred and twenty-six feet ten inches 

 in length, eleven feet four and three-quarter inches in depth, 

 and twenty-one feet between centres, formed of the ordinary 

 trough section, braced with wrought-iron tie bars and channel 

 struts, stiffened with ladder bracing. The roadway is eighteen 

 feet in the clear throughout the bridge, and is formed of tarred 

 metal, upon M^rought-iron buckled plates. The north end of 

 main bridge rests on a concrete abutment, the other approach 

 being formed of six non-continuous wrought-iron lattice girders, 

 sixty feet nine inches long, five feet four and a-quarter inches 

 deep, and nineteen feet centres, with the cross girders resting 

 upon the top booms. The abutment at this end is also formed of 

 concrete. The piers for main spans are formed of cast-iron bottom 

 lengths six feet diameter, with top lengths consisting of five feet 

 diameter wrought-iron cylinders, braced with wrought-iron dia- 

 phragm bracing, connected to bottom lengths by cast-iron conical 

 lengths connected with transverse bracing. The piers for approach 

 spans consist of cast-iron screw cylinders two feet six inches 

 diameter, with four feet six inches diameter of screw. Owing to 

 difficulty experienced in screwing, pits were sunk and screw ends 

 of cylinders stepped in concrete Traffic commenced over the bridge 

 on March 17, 1886. 



The following bridges of the same type have also been con- 

 structed :■ — Namoi River Bridge, at Gunnedah, two spans, one 

 hundred and twenty-seven feet three inches; designed in 1881. 

 Namoi River Bridge, at Yellow Bank, one span, one hundred 

 and twenty-six feet ; designed in 1882. Namoi River Bridge, at 



