SCHUYLKILL PERMANENT BRIDGE. 57 



tal on which dividends will be made, will encrease by the 

 addition so made. The sum mentioned in page 28 (218000) 

 as being the probable amovmt, was conjectui-al, and is not ex- 

 act. The following is as correct a statement as can now be 

 made ; though it may not be entirely accurate. It is founded 

 on the probable result of the year 1807. 

 Number of Shares completed on which dividends 



will be made is 19567 at S 10. B 195,670 



The sum funded, or borrowed on loan. Is S 4-2000 

 Interest at 6 per cent, is - - S 2520 

 The probable contingent expen- 



ces of eveiy description. - 2356 67 

 The Revenue for 1 807, will be 



S 14000, at least 



Although the Revenue is fluctuating, according to circum- 

 stances annually occurring, yet it has, on an average, constant- 

 ly progressed in an encreasing amount. This will be seen by 

 recurring to the sum produced by the floating bridge, as here- 

 tofore mentioned, and that now arising from the tolls of 1807. 

 There is yet a small proportion of unliquidated debt. 



COFFER DAMS AND PIERS. 



It is almost impracticable to give an intelligible de- 

 scription of a coffer dam, without technical language, 

 and a draft or model. It is calculated for excluding 

 the water of a river, in which a pier is to be erected on 

 a stable foundation ; and for this purpose, to give ac- 

 cess to the bottom, or bed, with safety; and, without 

 danger or impediment, to ensure the accomplishment 

 of the work. It is 2i fixture, and entirely different from 

 a batterdeaii, which is a tight vessel or box, in which 

 the masonry is carried on as it floats ; and, being at first 



