A STATISTICAL ACCOUNT OF THE 



^' On the 5th September the first stone of the pier was laid. 

 This day we fortunately kept the water out all day ; the ma- 

 sons worked 13 hours xvithoiit refreshment ; except a little 

 drink. We were now unanimously of opinion, that our diffi- 

 culties could be overcome ; nevertheless, we were obliged 

 to work night as well as day, when the tide answered," [the 

 leakages alwavs increased, owing to the greater head of wa- 

 ter at high tide] " until we got above low water mark. We 

 were then at ease ; but little pumping afterwards. The wa- 

 ter shoots^* laid in the dam, served to regulate the tide after- 

 wards on all occasions, until the masonrj' was finished." 



* Water shoots were tubes, in the first, and trunks in the second dam, fur- 

 nished with valves, or shutters, so , as to permit the exit of water, but to 

 repel its entrance, and to be opened, or entirely closed at pleasure. — 

 They were placed just above low water mark ; and while the dam was 

 filling with puddle, suffered to remain open for the flux and reflux of the 

 tide ; or shut when circumstances required. The dam could of course 

 be always emptied to low water mark, w^ithout pumping ; and by clos- 

 ing' the shoots, the tide was entirely excluded. But a great length of 

 time elapsed, while the puddle was filling, and consolidating, before it was 

 safe entirely to exclude the tide. The water, inside the dam, was a 

 great counter balance ; not only to the pressure without, but to that of 

 the settling puddle. None but those who ha%'e experienced it, can con- 

 ceive the almost resistless force of earth, while consolidating ■- and the 

 puddle of these dams consisted of several thousand cart loads. The ad- 

 mitting and excluding the water, required great care and judgm-cnt ; and 

 frequent trials were made, before the risque was encountered of the entire 

 exclusion of the tide. Before the earth of the puddle was suflficiently em- 

 bodied, to sustain itself, the woi-k had to support not only its weight, but 

 the immense force and irregular protrusions and pressures, of parts differ- 

 ently composed, and settling faster or slower than others. 



Every kind of earth, or substance, any wise proper, was tried for filling 

 or puddle. 



Crude brick or potter's clay, settled unequally, and cracked when other- 

 wise consolidated. Tempered clay w.is little better. 



River mud was bad ; it had some of the properties of clay. 



Gravel, was good for the filling of the abutments ; but not rj-oper for 

 the dam. So was it with sand. 



