ENGINEERING. 



257 



iron. The cables are to be of Bteel links and 

 pins, which are required to posses a final break- 

 ing strength of at least 80,000 pounds to the 

 sijuaiv indi, and which will be subjected to a 

 tension in the bridge of 20,000 pounds per 

 square inch. The pins are to have the form of 

 a perfect cylinder between head and nut. The 

 links iiear the middle of the span will be 25 



feet long between the centres of the eyes, and 

 as they approach the towers are to be longer 

 in such proportion that the horizontal distance 

 between the eyes shall remain 25 feet. '1 In- 

 largest links in their middle will not have a 

 greater sectional area than eight inches. The 

 towers below the track of the railroad will be 

 formed of cells of wrought-iron, and above the 





SC8PKN8ION-BBIDQE OVEB THE EAST RIVER, BROOKLYN, N. T. 



track will have eight columns 80 feet high and 

 11 feet in diameter. Each chamber in the 

 lower tower will have twelve saddles and two 

 pairs of compensating levers. These and their 

 attachments will be carried by a frame that 

 extends in both directions across the saddle- 

 cliambers and over the heads of all the columns 

 of the tower. All the parts of the saddles and 

 the lever attachments for the stay system will 

 be worked in together upon this frame ; and so 

 that the parts will move together sufficiently to 

 compensate the expansion and contraction of 

 the main back-stays beyond what the tower 

 itself sustains. The saddles will move by steel 

 rollers upon steel faces under the carrying- 

 frame. The anchorage of the cables will be in 

 the solid rock at both ends. It is expected 

 that this bridge will pave the wny for a new 

 railroad to the West, with a route between 

 "ew York and Chicago only 921 miles long, a 



.ving of 50 miles over any existing line. 



A new bridge is to be constructed at Mon- 

 treal, about four miles from the Victoria 

 Bridge, which is to be called the Royal Albert 

 Bridge, and will be the longest structure of the 

 kind in the world. Its whole length, includ- 

 ing the portion built over the land, will be 

 15,500 feet, almost exactly three miles. It will 

 start from the level of Sherhrooke Street in 

 Montreal, nnd pass through the town at the 

 height of about 90 feet, with distances of 150 

 VOL. xvi. 17 A 



to 200 feet between the piers. Between the 

 city and St. Helen's Island, whose centre is of 

 the same elevation as the roadway of the bridge, 

 there will be six spans of lattice, one of 550 

 feet and the rest of 300 feet. The roadway 

 will have but a single track ; but on the island 

 side-tracks and a crossing-station will be made. 

 From the centre of this island to the water's 

 edge four spans of 240 feet will be required. 

 On the other side of the island there will be 

 twenty-one spans of 200 feet to the other 

 channel, and over that live spans of 200 feet, 

 the roadway on this side having a falling 

 gradient of 1 : 100. On the lower side of the 

 river embankments will be made, and connec- 

 tions established with the Montreal, Portland 

 & Boston, and the Grand Trunk Railroads. 

 At the other end there will be a junction with 

 the Quebec, Montreal, Ottawa & Occidental 

 Railway ; the distance between the two junc- 

 tions is five and a half miles. In the navigable 

 channel the piers, which will be like those of 

 the Victoria Bridge, with heavy ice-breakers, 

 will have to be put down with caissons, in a 

 channel 40 feet deep, where the current is seven 

 miles an hour. The superstructure will be of 

 iron lattice-work, each pier being crossed by 

 four girders, placed 18 and 14 feet apart; be- 

 tween the. inner girders will be two street-oar 

 tracks; between them and the outer girders 

 will be the roadways for teams, and on .pro- 



