those at the end 210 feet each. These arches are composed of cast iron, but the piers and abutments are of stone, forming altogether the most stupendous bridge, of such compound materials, in the world. The central arch of Southwark Bridge exceeds in span the famous iron bridge at Sunderland, by four feet, and of the Rialto of Venice, by 167 feet. The weight of the iron alone is more than 5,508 tons. The foundations of the piers are twelve feet below the bottom of the river; and the bases of the immense timber piles upon which those foundations (with the wooden platform 24 feet thick intervening) rest, are 263 feet lower. The distance between the two abutments is 708 feet: the entire expense incurred by the construction of this bridge amounted to 800,000l. It was completed and opened for public use in March, 1819.

Blackfriars Bridge. This bridge was built by Mr. Robert Mylne, between the years 1760 and 1769, at an expense of 152,840l. It has eight piers and nine elliptical arches. The centre arch is 100 feet wide, those on each side 93, the next 80, and the adjoining 70. The length is 995 feet, the breadth of the carriage-way 28 feet, and that of the flagged footways 7 feet each. Seen from the water, a recess appears over each pier, fronted by two Ionic columns, which support a correspondent recess above. The carriage-way of this bridge has recently been lowered, and a new road made, upon the system of Mac Adam; the whole carriage pavement of Bridge Street has also been taken up, and the road newly-formed after the same plan. St. Paul's church appears from this bridge in all its commanding majesty.

Waterloo Bridge may be regarded as one of the noblest structures of its kind in the world. It was commenced in 1811 and completed in 1817, having thus been raised with a rapidity unexampled in the history of edifices of this description. Crossing the Thames from a point between Somerset House and the spot where, until recently, stood the remnant of the Savoy, to the opposite shore of Lambeth Marsh, it connects the populous line of the Strand with a new line of street to the Obelisk in St. George's Fields. The engineer who gave the plan was Mr. G. Dodd; but

that gentleman disagreed with the company engaged in the undertaking, soon after its commencement, and the late Mr. Rennie has the merit of conducting it to so noble and successful a termination.

Like some of the bridges of the ancients, the roadway over Waterloo Bridge is level, a circumstance highly favourable to the draught of carriages over it, and an addition to, rather than any subtraction from, its beauty. It has nine grand arches, each 120 feet span; the piers, which are twenty feet thick (and each of which stands on a platform, based on 320 piles), support Tuscan columns in the manner of Blackfriars Bridge. The entire structure, externally, is of granite, the balustrades being of Aberdeen granite, and the remainder of that of Cornwall. In order to produce a level from the Strand to the Bridge (the intervening space being a considerable ascent from the river's brink), it was necessary to turn a succession of arches, on which to carry the intended road: three times the number of these additional arches were required on the Surrey side, and the whole are composed of brick. Upon the entire works, comprehending the roads themselves leading to and from this truly magnificent erection, a sum consisiderably exceeding one million sterling was expended.

The toll-lodges, two at each end of the Bridge, are neat little buildings in the Doric style. There are metal turnstiles attached to each, (intended to admit the passage of one person only at a time) at every movement of which some machinery, connected with an index in the toll-house, is worked, and, the index being secured in a locked box, the number of persons who have passed may be known by those in possession of the key, at any period of the day, with the utmost exactitude.

The dimensions of this structure are as follow: Length of the stone-work between the abutments 1242 feet; length of the road on the Surrey side, which is supported by forty brick arches (under one of which the street is continued from Narrow wall), 1250 feet; length of road supported on brick arches, on the Strand side, 400 feet; width within the balustrades 42 feet; width of carriage road 28 feet, and of each foot pavement 7 feet; span of each arch 120 feet; extent of water-way, in the clear, 1080 feet.

One other peculiarity connected with the building of this Bridge is deserving of mention. The centres upon which the arches were turned were constructed upon an entirely novel principle, the idea of which originated with Mr. Rennie, arising from a wish in that gentleman to prevent the defections usually occasioned in their forms by the weight of the materials temporarily resting upon them, from taking place in the erection of this structure. This eminent engineer discovered, that if the loading rested upon the timbers longitudinally instead of laterally, the defect above-mentioned would be obviated; and he applied this principle so effectually in the present instance, that the centres never sensibly changed their forms in the slightest degree. When the timbers were taken away, the arches sunk about one inch only in the middle; whereas it has been remarked, that those of the Pont de Neuilly, near Paris, the plan of which much resembles these, sunk no less than eighteen inches immediately upon their centres being removed from them. The ceremony of opening this bridge, upon the 18th of June 1817, the anniversary of the victory of Waterloo, was attended with circumstances of unusual pageantry, the Duke of Wellington, and his present Majesty, then Prince Regent, with a grand military cavalcade, being present at the spectacle.

Westminster Bridge was built between the years 1739 and 1750, and cost 389,500l. It is 1223 feet long, and 44 wide, comprising 14 piers, and 13 large and two small semicircular arches on its top are 28 semi-octangular recesses, twelve of which are covered with half cupolas. The two middle piers contain each 3000 solid feet, or 200 tons, of Portland stone. The middle arch is 76 feet wide; the two next 72, and the last 52 feet. The whole free waterway between the piers is 870 feet. This bridge has been much admired, but perhaps too much praise has been bestowed upon it at the expence of Blackfriars, which certainly is but little less beautiful, though, from a necessary inferiority in its dimensions, not quite so grand. The architect was Mons. Labelye, an ingenious Frenchman. The road-way was M'Adamized (as the phrase is) in 1824..