Originally pubished in 1832 for The Penny Magazine of the Society for the Diffusion of Useful Knowledge.

We avail ourselves of the permission of Mr. Brunel, iun., to copy his beautiful lithographic engravings of Suspension Bridge about to be erected over the Avon, at Clifton. The above plate will furnish some idea of the beauty of the situation of this intended bridge; and the following particulars will give a notion of the boldness of the undertaking :-

• Distance from centre to centre of piers 500 feet.
• Height of roadway above water 240 feet.
• Width of roadway, 20 feet;-two footways of 6 feet, 12 feet.-Total, 32 feet.
• The road being in the centre, the footpaths are on each side and outside of the chains and suspension rods.
• The Egyptian gateways will be on a scale equal to those of some of the largest of the ancient models.
• From the roadway to the top of the Sphynx will be about 100 feet.
• The gateway will be about 40 feet high in the clear.
• The base on which the south pier stands, will be 120 feet in height.

The bridge is to be thrown across the river Avon, joining the high rocks on either side, called the St. Vincent Rocks, about one mile below Bristol; and consequently all the shipping of Bristol, including East and West Indiamen of the largest class, will pass under it. It is considered by some that the notion of suspension bridges was derived from the rope bridges of South America. A very remarkable bridge of this sort, that of Penipé, is described by Humboldt, in his ‘Vues des Cordillères; and, from a plate in that fine work, we copy the following representation of this bridge.

Such a bridge must be very inconvenient, as the road way is bent like the cables.

There are several ancient suspension bridges in China and in Thibet sufficiently strong to enable a man with a load, and even a beast of hurthen, to pass with security. But such structures are manifestly not to be compared to those splendid monuments of science which afford a safe and broad passage to any number of horses and carriages; and the situations of which are never productive of any inconvenience. The principle upon which suspension bridges are constructed is thus described:-
” In these the flooring or main body of the bridge is supported on strong iron chains or rods, hanging, in the form of an inverted arch, from one point of support to another. The points of support are the tops of strong pillars or small towers, erected for the purpose. Over these pillars the chain passes, and is attached, at each extremity of the bridge, to rocks or massive frames of iron, firmly secured under ground. The great advantage of suspension bridges consists in their stability of equilibrium, in consequence of which a smaller amount of materials is necessary for their construction than for that of any other bridge. If a suspension bridge be shaken, or thrown out of equilibrium, it returns by its weight to its proper place, whereas the reverse happens in bridges which are built above the level of their supporters. (Encyclopædia Americana vol ii p.269)”

The Europeans of the seventeenth century had conceived the principle of suspension bridges, and such a structure is described by Scamozzi, an Italian architect, in his work Del Idea Archi, published in 1615. Eighty years ago, the English threw over the Tees, at Winch, near Durham, a bridge of iron-wire, which served for foot-passengers. In the beginning of the present cen-tury, by means of chains placed close to each other, carrying cross-beams and planks laid longitudinally, we constructed bridges, over which workmen might pass with loaded wheelbarrows. Such were the bridges established on iron chains, and thrown from one eminence to another, for the purpose of carrying away the earth to be removed in order to disengage the blocks of stone which were then blown up with gunpowder, and employed afterwards to form the great Breakwater at Plymouth. Towards the end of 1816, the Scotch introduced the use of suspension bridges, but without extending them, at first, to the passage of horses and carriages. As early as 1813, Mr. Telford proposed to construct a bridge of suspension over the Mersey, at the place where the Duke of Bridgewater’s canal communicates with that river. This bridge was to have only four supports, and to be composed of three arches, having, respectively 500 feet, 1000 feet, and 500 feet in span; making a total length of 2000 feet. The boldness of this project frightened the capitalists to whom it was proposed; but it had, at least, the advantage of drawing public attention to this new species of constructions. It caused a number of experiments to be made on the strength of iron, and on its utility when employed for suspension bridges.

Captain Brown, who subsequently built the fine suspension bridge at Hammersmith, was the first engineer who erected such a bridge for heavy vehicles in Great Britain. His bridge over the Tweed, at Kelso, was completed in 1820. It is 300 feet in length, by 18 feet in width. The most remarkable bridge of suspension in existence is that constructed by Mr. Telford over the Menai strait, between the isle of Anglesea and Caernar-vonshire in Wales. It was finished in 1825. The roadway is 100 feet above the surface of the water at high tide. The opening between the points of suspension is 560 feet. The platform is about 30 feet in breadth. The whole is suspended from four lines of strong iron cables, by perpendicular iron rods 5 feet apart. The cables pass over rollers on the tops of pillars, and are fixed to iron frames under ground which are kept down by masonry. The weight of the whole bridge, between the points of suspension, is 489 tons.

In France there is a very pretty suspension bridge over the. Seine, at Paris, which is now known, in consequence of the conflict of July, 1830, as the Bridge of Arcole.

In the United States such bridges are to be found, though not of the dimensions of the English. That over the Merrimack, at Newburyport, is a curve whose chord measures 244 feet. That over the river Brandy-wine, at Wilmington, has a chord of 145 feet; that at Brownsville, over the Monongahela, measures 120 feel between the points of suspension. Another, in its vicinity, forms an inverted suspended arch, with a chord of 112 feet