With the view of keeping 4 feet of water on the apron at the toe of the dam, and thereby breaking the force of the fall, by its action on a body of water, there has been constructed, at a point 300 feet below the main dam, a secondary dam of timber and stone, which is 200 feet long and 9 feet high. The abutments of this secondary dam, with two piers of crib work, filled in with stone, have been used for the purpose of a bridge across the river, and will remain a bridge to accommodate the public and for the use of the keeper of the gate house.

The construction of the new dam was vigorously commenced by Messrs. McCullough, Black & Co., early in the spring, under contract, to raise the same so high by the 1st of November following, as to throw at least two feet of water into the tunnel of the aqueduct. This requirement of their contract they have not fulfilled which is to be regretted, ;

mainly on the ground that the work could not be left in as secure a condition against the spring floods, as it would have been left, had this condition of the contract been complied with. The contractors urged in excuse, the great difficulty in procuring sufficient quantities of large stone, and of a suitable quality, and the consequent failure, by their sub-contractors, in the delivery of such stone ; which difficulty was enhanced by the rejection of every stone not deemed of the most durable quality. The work, on the whole, has been prosecuted, with the exception referred to, with commendable perseverance and energy, and the dam can be made to throw into the aqueduct the water required, early in the ensuing^summer, and can be conveniently completed during the summer months.