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appearance, extends across the river. If so, the foundation of the centre piermay be laid on rock. Nothing positive has been ascertained on this point, noris it very important that there should be a rock foundation. If rock can onlybe found at a great depth, a pile foundation will be as safe, and much cheaper.Or a common timber foundation may prove sufficient, if the ground should befound favorable to it. As the river bed consists of gravel, its character willwarrant the stability of almost any kind of foundation, provided it is alwaysguarded against undermining by an extensive riprapping or stonefilling.

3. GENERAL DESCRIPTION.

The plan of the bridge, as has been remarked before, is adapted to the profileof the river bed, in line with Main street: the dimensions, therefore, havereference to that locality. The centre line, or axis of the bridge, is supposed tobe located at a distance of 55 feet from the lower side of Main street. An openstreet, as a continuation of Main, would, therefore, be left between the lowerreturn wall of the abutment and the houses now fronting the wharf, of 75 feetwide. The length of the bridge, from centre to centre of the abutments, is 1576feet, total length, including approaches, 2070 feet. Two spans are proposed,which will meet in the centre of the river upon a gigantic stone pier, of 200 feethigh. Three-fourths of the whole suspended weight of the bridge will be sup-ported by this pier.

The river front of the Cincinnati abutment will be opposite the corner ofWharf and Main, and nearly in line with Wharf street. It will, therefore, notpresent any impediment to the current of the river when high. The housesfronting the bridge, will be protected by the return walls against the current.These walls extend from the abutment to Front street, leaving the latter entirelyfree. The length of abutment is 50 feet, the extreme width across the returnwalls, opposite Water street, will be 44 feet, and reduced to 38 feet at Front street.There will, therefore, be a space occupied on the public landing of 290 feet longby 44 feet wide, leaving the wharf between the abutment and the edge of theriver entirely free and open. The approach on the Covington side is verynearly the same as on the Cincinnati side. The uniformity and symmetry ofthe two ends will add much to the splendid appearance which this great struc-ture will present to the eye of the traveller who approaches the city by theriver.

The tower in the centre of the river will, on account of its gigantic propor-tions, form the most conspicuous part of the whole structure. The total heightof this masonry from the foundation will be over 200 feet, and 194 feet abovelow water mark. Its lateral dimensions are proportioned to its height. Thisstructure has been planned with a view of obtaining the greatest stability, withthe least amount of material, and with reference to the comparative expense oflabor and material. Its main body consists of two solid walls of 12 feet by 20feet on top, and 15 feet by 43 feet on bottom, carried up 200 feet, parallel toeach other, at a distance of 45 feet apart from centre to centre, in the directionof the river. A connection is formed on the foundation and by two archesabove. In order to increase the stability of these walls, they are strengthenedby buttresses, which are 15 feet wide at bottom, 7 feet at top, and batter 14 feet.The cubic contents of this pile of masonry will be 12000 perch of 25 cubic feeteach. No part of this masonry can be reduced with safety: it will be explained