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11. COMPARATIVE MERITS OF ONE AND TWO SPANS.

When I first reflected on the plan of a suspension bridge at Cincinnati , andbefore I had attained that knowledge of locality which is indispensable to thedesign, I expressed myself in favor of one single span, and delineated thegeneral features of such a structure. If the river bed was such that the foun-dation of the tower could only be obtained at a very great expense, and if theerection of a centre pier would prove an impediment to the navigation of theriver, then a single span would be entitled to a preference. But as no seriousobjections can be made to a pier, and its foundation will not be attended withany very great expense, the plan of two spans should be adopted, provided itoffers superior advantages over one span. The objection which can be urgedagainst one single span, next to an increase of expense, is the great space whichwould necessarily be occupied by the towers and long return-walls on bothshores. Such ground could be easier spared on the Covington than on theCincinnati side. It would also be more difficult to attain that elevation of floorwhich is proposed. On the other hand, it is true, that a single span, withoutany pier, would appear to be more independent of the river. No fear, however,need be entertained that the masonry of the tower, if constructed as proposed,could ever be affected by the water. Its protection by an ice-breaker, which iseasily kept in repair, its great weight, and the high elevation of the floorabove the river, will, if the foundation is executed with due care, guarantee itssafety. The reasons which decide in favor of two spans, are:

1. The greater adaptedness of the approaches to the locality and the localwants on the Cincinnati side.

2. The abutment and return-walls on the Cincinnati side will occupy lessspace.

3. They will also be further removed from the edge of the river, and leavethe wharf under the bridge unobstructed.

4. If the site, proposed here, is chosen, the capacity of the wharf will, for allpractical purposes, not be reduced.

5. It is easier to attain that high elevation of floor which is desired.

6. A greater section of waterway will be obtained by two spans than by one.

7. Saving of expense.

11 INVESTMENT.

Who has imagination and foresight enough, to foretell the number and thewealth of that people which, one hundred years hence, will crowd both shoresof the Ohio at Cincinnati ? Less than one hundred years ago the greater partof this Union of states was one vast unbroken wilderness, traversed by nonebut prowling savages and beasts of prey. On the spot where your city is nowlocated, fifty years ago, no signs could be discovered of that civilization whichis indispensable for the existence of the whites,—no sounds could be heard ofthat industry which our race has so vastly developed. Where now can be wit-nessed at each hour of the day, scenes of great commercial activity, the bustleof the arrival and departure of hundreds of travellers, there reigned, fifty yearsago, the unbroken solitude of a dense forest. Where now the bosom of theOhio is ploughed up and down by hundreds of swiftly moving steamers, con-veying thousands of intelligent beings, transporting the products of industryand of the soil, and distributing the necessaries, comforts, and luxuries of life8