Democratic Sentinel, Volume 3, Number 27, Rensselaer, Jasper County, 15 August 1879 — BRIDGES. [ARTICLE]

BRIDGES.

A Few of the Highest in the World—The East River Bridge Comparatively a Dwarf. [From the Brooklyn Eagle.] The immense height of the towers for the support of the Forth bridge has created some surprise and no wonder, when it is taken into account that when completed they will be the highest building of any kind in the world. Science will, therefore, wait with some anxiety their completion. The height of the towers on the island of Inch Garvie, midway between South and North Queensferry, will be 560 feet, to support a bridge 150 feet above highwater mark, but the reason for this great altitude is that in the generality of suspension bridges the towers are built on the land on either side of the span, and were this the case in the Forth bridge towers of 150 feet less height, or 410 feet, would be sufficient; but this is impossible, from the great length of the bridge. It seems that by natural laws there is a limit to everything on this earth—that is, that man can go to a certain length and no further, as, for instance, in telescopes nothing larger than Lord Ross’ having been perfected for many years. In reference to buildings, a correspondent the other day quoted St. Rollox stalk 430 feet high. St. Paul’s Cathedral is ab6ut-460 feet to top of the dome, St. Peter’s at Rome 480 feet, the pyramids of Egypt, at least the great pyramid, is 180 feet at present in its imperfect shite, but by calculation would reach 500 feet in height when finished. When it is remembered that this structure only reaches this height with a base of about 26 acres, it will be a very difficult matter to raise the Forth bridge towers to 560 feet with a small base. These towers are to be formed of solid masonry to a certain height, and then by groups of iron pillars girded together in layers upward. The Niagara suspension bridge has one large span of 821 feet; the railway track above the water is 245 feet, or 95 feet higher that the Forth bridge; the towers are only 60 feet high, being built on either side of the shore. The Allegheny bridge has two large.spans of 344 feet each, and the towers are 45 feet high. The Covington and Cincinnati bridge has a span of 1,057 feet; its height above low water is 103 feet, and the towers 230 feet high. The bridge seems to give the best proportion to the Forth bridge, which is 1,680 feet for two spans, 150 high, and towers of 560 feet. Those we have mentioned are finished and in working order; and we may mention also the East River bridge, connecting New York to Brooklyn. The towers of this bridge are also built upon the land, and are 278 feet high. The single span is 1,595 feet long, or only 85 feet less than the Forth bridge, while the total length is 5,989 feet. There is, therefore, no doubt that the Forth bridge, when completed, will be an engineering triumph.