At 300 feet below the main dam, a second dam is in progress, which is to be 9 feet high, constructed of timber, stone and gravel, which will set the water back over the of the main and form a to check the water as it falls on it. apron dam, pool A coffer dam was constructed in the river to inclose about 120 feet of the work, from which the water was pumped by a steam engine, and a concrete foundation laid down on a very firm hard pan. The remainder of the foundation was made by sinking timber piers at suitable distances, running parallel with the dam, and filling the spaces between them with concrete masonry. In preparing the specifications for this work, the method and order of prosecuting it was particularly designed, and from which no material departure has been found necessary the structure is now nearly completed. ;

The contractors, Messrs. McCullough, Black, McManus, and Hepburn, have evinced a highly commendable energy and ability in its prosecution. This dam sets the water of the river back five miles, and forms a reservoir of about four hundred acres, and has rendered it necessary to construct several new roads and bridges as a substitute for those covered by the flow, the principal of which is the Somerstown turnpike. The grounds lightly flowed on the margin, have been excavated so as to give 4 A feet for the least depth of water. From this reservoir the water flows into the bulk-head, at the upper end of the tunnel, from a level averaging 10 feet below the surface.