THE 



ANNUAL OF SCIENTIFIC DISCOYEEY, 



MECHANICS AND USEFUL ARTS. 



SUSPENSION BRIDGE OVER THE OHIO AT WHEELING. 



FROM the report of the engineer who has charge of the Wheeling 

 Suspension Bridge, we derive the following facts. The span of the 

 bridge from centre to centre of the supporting towers is 1,010 feet, 

 which is 152 feet longer than the bridge at Friburg in Switzerland, 

 the longest span hitherto constructed. The height of the flooring is 

 97 feet above the low-water level of the river, and 58 feet above ^the 

 highest flood ever known, except the celebrated one of 1832. The 

 towers over which the suspension chains pass are built upon the abut- 

 ments, and that at the eastern side rises 153 feet above low-water, and 

 60 above the abutments; the other tower varies slightly from this 

 measurement. The wire cables which support the flooring are 12 in 

 number, 1380 feet long, and 4 inches in diameter. These cables rest 

 on iron rollers, placed on the summits of the towers, the movements 

 of which will relieve the towers of the strain consequent upon the 

 contraction and elongation of the wires, occasioned by the changes of 

 temperature. The flooring is 24 feet wide, divided between a carriage- 

 way of 17 feet, and two footpaths of 3 feet each. The length of the 

 wood-work resting on the cables is 960 feet, and its weight is 546 

 pounds per lineal foot, making a total of 524,160 pounds, or 262 tons. 

 In each cable there are 550 strands of No. 10 wire. The weight of 

 each lineal foot of the 12 cables, which are composed of 6,600 strands, 

 is 330 pounds, making, with the weight of the timbers, bolts, &c., a 

 total of 920 pounds per lineal foot, or 634 tons as the permanent weight 

 of the bridge. But, in addition to its own weight, it is intended to 

 support the largest weight that can be brought upon it at one time. If 

 filled from one end to the other with a double row of the heavy wag- 

 ons used on the National Road, it is calculated that an additional weight 

 of about 600 tons might possibly be brought upon it. But it is ascer- 

 tained by a machine, that the aggregate strength of the 6,600 strands 



