BRIDGES. 



495 



stl*uction ; the design furnished by William Weston, 

 esq. of Gainsborough in England, a celebrated hy- 

 draulic engineer. An idea of its magnitude may be 

 framed, when it is known that 800,000 feet of tim- 

 ber (board iileasure), were unavoidably employed 

 in and about it. Every disadvantage to which such 

 difficult undertakings are subject (the rock being in 

 S'Uiidry parts, nearly bare, and affording no footing 

 for the piles), opposed the progress of this, so that 

 it could not be ready for the commencement of the 

 masonry until the 25th of December, 1802, when the 

 first stone was laid, and the work continued in a se- 

 vere winter to the height then proposed. 



The masonry is executed on a plan suggested by 

 the mason, (T. Vickers,) uncommon, if not new. 

 The walls of the abutments and wings are perpen- 

 dicular, without buttresses; and supported by inte- 

 terior offsets. These are found completely compe- 

 tent to support the pressure of the filling, without 

 battering or contreforts. The abutments are 18 

 feet thick. The wing walls nine feet at the foun- 

 dations retiring by offsets, till at the parapets they 

 are only 18 inches. The eastern abutment and wing 

 walls are founded on a rock. Those on the western 

 side are built on piles. There are upvyards of 

 r^SOO tons of masonry in the western pier. Many 

 of the stones, composing both piers, weigh from three 

 to twelve tons. A number of massive chains are 

 stretched, in various positions, across the piers. 

 These are worked in with the masonry, the exterior 

 whereof is clamped, and finished in the most sub-, 

 stantial and workmanlike manner. 

 The frame of the superstructure was designed and 



