BRIJJGES. 



foundation of the abutment, and seven feet wide in 

 the bottom. From the end of the angle, they are 

 continued in a parallel line with each other, one hun- 

 dred and three feet further, on a gradual t^per to 

 four feet, where they terminate. The exterior of 

 this masonry is battered half an inch to the foot, 

 whilelthe interior is rather more than perpendicular ; 

 so that the filling has little or no pressure on the 

 side walls, but will settle in perpendicular lines. 



The wing wails on the west or Pennsylvania side, 

 are eighty-five feet in length from the front of the 

 abutment, extend about eighteen feet? into the bank, 

 and spread or splay sixty-six feet, bein^ the width 

 of the street leading to the bridge. 



In laying the exterior courses of the foundations of 

 the piers, great care was taken to select fiat and 

 long stones, running many feet into the piers. Oa 

 these, and throughout the whole interior, are laid 

 large rough stone of vast weight, and the whole 

 closely filled in with building stone. The depth of 

 these foundations vary several feet in different parts 

 of the piers, owing to the irregular surface of the 

 rock, (in some places forming a pretty regular bason) 

 and this is as an additional security against their 

 being moved by ice, rafts, or other floating substan- 

 ces coming against them. 



An offset of six inches is made on these foundations, 

 \vhen the cut stone commences, the pier here receiv- 

 ing its proper shape and dimensions, which, in this 

 place, is sixty-eight ftet in length, and twenty-two 

 in breadth, with the end up stream of a semicircular 

 form.. The levelling up of the foundation, and all 



