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each side of the centre line, by reverse forty-chain curves, for 

 a distance equal to one span of 144 feet, two spans of 176 feet, 

 and one of 176J feet, at which point it reaches the Queensferry 

 tower, and attains a width apart of 100 feet, forming two dis- 

 tinct lines of railway. It then runs parallel at this distance 

 apart for the length of the two 1,700-feet spans for the four 

 towers, and for the two spans between the towers of 165 feet 

 each. The lines will gradually converge by reverse forty-chain 

 curves, and regain the form of an ordinary double line of rails 

 as far as the north abutment. 



TAT BRIDGE. 



The Tay Bridge is now being erected to supersede the bridge 

 that collapsed during the gale in 1877. The new bridge was 

 designed by Mr. W. H. Barlow, C.E., of London, and consists 

 of 85 spans, being a total length of 10,515 feet, or nearly two 

 miles. There are four brick arches and thirteen spans over 

 navigation (eleven of them being 245 feet each and two of them 

 227 feet each), the two latter being 28 feet 9 inches deep. The 

 piers are of wrought-iron, supported on iron cylinders sunk 

 20 feet into the river bed, and filled with concrete and brick- 

 work. The height of the under members of the girders above 

 high water is 77 feet. The contractors are Arrol & Co., of 

 Glasgow, and the cost will be £700,000. 



SUSQUEHANNA BRIDGE. 



The Susquehanna Bridge is on the Baltimore and Ohio 

 Biver, and is 6,315 feet long, having four spans of 480 feet, 

 and one span of 520 feet. 



HENDERSON" BRIDGE. 



The Henderson Bridge is also across the Ohio River, in Ken- 

 tucky, U.S.A., is 3,200 feet long, with one channel span of 725 

 feet ; the remaining spans are 250 feet each. It is 103J feet 

 above low water, and 57 feet above high w r ater. The approach 

 is by trestle work three miles in length, and the cost has been 

 £372,000. 



st. john's bridge. 



The St. John's Bridge is a cantilever bridge 447 feet between 

 the piers. It is built across the river before it enters the Bay 

 of Fundy, and at a point where it is contracted between two 

 rocky ledges to a width of about 500 feet. The tide rises and 

 falls about 22 feet, producing violent currents, so that a canti- 

 lever bridge was the most feasible structure. The rail level is 

 75 feet above tide. The erection of this bridge occupied 90 

 days, and the structure is capable of carrying a moving load of 

 one and a quarter tons, and a wind pressure of 40 pounds per 

 superficial foot. It was designed by Mr. Abbot, and built by 



