SCHUYLKILL PERMANENT BRIDGE. 43 



directed by the building committee ; and on the 25th of De- 

 cember 1802 began to be formed. It consists of large foun- 

 dation and smaller stone intermixed. Roach lime and sharp 

 sand cover and fill the interstices ot each layer of these stone ; 

 which are all well rammed ; and, reaching the rock, compose 

 a solid mass, four feet thick, filling the whole interior of the 

 dam ; the area whereof is 42 feet six inches in breadth, by 92 

 feet in length. On this foundation, the cut stone was laid, 

 and the pier shaped to its proper dimensions ; Avhich are here 

 30 feet in breadth, by 71 feet 6 inches in its extreme length ; 

 the ends being semicircular. It continues of these dimensions 

 to the first offset, about four feet from the foundation. — There 

 are six offsets to low water mark ; each diminishing the pier 

 about four inches ; so that at that point it is twenty six feet 

 eight inches in breadth and sixty seven feet two inches in length. 

 There are from this point, to 18 inches above high water mark, 

 three offsets, each diminishing the pier 10 inches. So that 

 the dimensions, at this point, are twenty one feet eight inch- 

 es in breadth, and sixty three feet two inches in length ; the 

 whole continuing semicircular at the ends. From this point 

 the pier begins to batter and the cut stone ceases. The ham- 

 mered stone, in range work, begins, and rising sixteen feet, 

 lessens regularly to nineteen feet four inches in width, and in 

 length sixty feet ten inches. When finished it will be in 

 height fifty five feet nine inches from the rock, and will be 

 neatly surmounted with cut stone, at each end, formed in 

 the shape of a half dome» The cut stone are all clamped at 

 every joint, with iron clamps, well secured. The outer ash- 

 lers are all laid in tarras m.ortar. There are a proper number 

 of headers, dove-tailed in each course ; running into the pier 

 many feet. On these are laid vast rough stone, some where- 

 of are twelve tons in weight. — These large stones of various 

 sizes, are common in the interior of the pier, which is laid 

 in a workmanlike manner, in common mortar, and properly 

 filled with smaller stone ; the whole being grouted and form- 



