44 ANNUAL OF SCIENTIFIC DISCOVERY. 



probably last as long as the other. The inside measurement of 

 the bridge will be 10 feet in the clear. Publicly opened Jan. 2, 1869. 



Tlie Nashville Suspension Bridge. — The floor of this bridge over 

 the Cumberland River, Tennessee, connecting Nashville and Edge- 

 field, to replace one destro3^ed during the war, is about 100 feet 

 above low-water mark. It has a carriage-way with a foot-path on 

 each side. Two cables, 8 inches in diameter, support the struc- 

 ture, the span being 650 feet and the roadway being 28 feet 2 

 inches wide. At the north end it is slightly higher than at the 

 other. It was built under the direction and superintendence of 

 W. F. Foster, C. E. 



Bridge over the Mersey. — One of the finest railway bridges in 

 Great Britain has just been thrown across the Mersey River, at 

 Runcom. It is a girder bridge 1,000 feet long, and is supported 

 on stone piers rising 75 feet above high-water mark. The span 

 of each division is 327 feet, and there are 97 arches, each of 60 

 feet span. By the completion of this bridge the distance between 

 London and Liverpool is shortened by 15 miles. The cost of the 

 structure was about $1,250,000. 



k Bridge over Seekonk River. — The Boston and Providence Rail- 

 road are constructing a bridge from India Point, over the Seekonk 

 River, on a plan which embraces some new features. The whole 

 length of the bridge is 876 feet, and the supports in the river are 

 iron cylinders filled with wooden piles and concrete. Six of these 

 cylinders are 6 feet in diameter, and contain 12 piles, which 

 were driven into the mud 40 feet, the cylinders being sunk 10 

 feet. Iron cylinders filled with concrete have been used before, 

 but driving piles within them, and the combining of wood and 

 concrete, is a new experiment. 



Projected Lever Bridge. — Under this name, Mr. Liscom, of Bos- 

 ton, has constructed a bridge by which he claims that he can span 

 streams or ravines 250 feet wide, without using in the process of 

 construction any piers or supports below, or suspensory chains 

 above, and doing away with braces and stringers. By weighting 

 the shore end properh^ he projects forward his bridge, gradually 

 extending it and adding corrasponding shore weights, till the 

 structure meets a similar projection in mid-stream from the other 

 side. He states that he has built, at a small expense, several 

 bridges on this plan, which apparently sustained the weight in a 

 satisfactory manner. A stream of 200 feet in width would require 

 260 feet of bridge. Many bridges, constructed on this principle, 

 are thrown across chasms in the Himalaya mountains, and in 

 India, where any support from below, during or after the construc- 

 tion, would have been impossible. 



Proposed Railroad Suspension Bridge across the Hudson River. — 

 The precise locality has not yet been determined, but it wjU be 

 somewhere between Verplanck's Point and Buttermilk Falls. The 

 proposed bridge is one link in the railway intended to connect the 

 Erie road with railroads on the east side of the river. The road 

 will run from Turner^s on the Erie Railroad, to Derby in Connect- 

 icut. 



The following are some of the dimensions of the proposed 



