C. F. MERCER, President of the Chesapeake and Ohio Canal Company. EXTRACTED--PAGE 55, DOC. NO. 10, 19TH CONGRESS, 2D SESSION.--EXECUTIVE PAPERS. "The difficulties of this passage (down Wills creek) are great, and continue for more than a mile. The ground then becomes favorable (_i.e._, in descending Wills creek from the west), permitting the canal to pass at the outskirts of Cumberland, to join with the eastern section. Adjoining Cumberland, the canal will receive a feeder from the Potomac for a supply below, and more especially to complete what is necessary in relation to the first subdivision of the eastern section. "This feeder is proposed to be made navigable, in order to accommodate the trade of the Potomac above Cumberland. Its length is one mile, its width at the water line thirty feet, its depth four feet. At its point of departure from the Potomac, a basin is formed in the bed of the river, by means of a dam erected at the first ledge above Cumberland. "This basin, comprehending an extent of about eight miles, will afford a constant supply of water, and also accommodate the canal trade of the Potomac. The levees around the basin, the dam, the guard lock of the feeder, and its aqueduct over Wills creek, are included in the estimate of this subdivision. "In the table of quantities and cost, this feeder is made to cost a very large sum (two or three words illegible in the MS.) if the dam above Cumberland is supposed to be ever changed from the above location. The aqueduct over Wills creek is computed to cost $41,601; the length of the aqueduct, seventy yards; the number of arches, three; the span of the arch, thirty feet; the height of the piers, sixteen feet." The above is a true copy. C. F. MERCER. May 10, 1833. * * * * * ENGINEER DEPARTMENT, WASHINGTON, August 10, 1833.