Several excellent stone bridges have lately been con structed upon the river Thames at Kew, Maidenhead, Henley, and Oxford; and not inferior to these are the bridges over the river Severn in Worcestershire and Shropshire. Five of these were designed and executed under the direction of Mr Gwynn, a native of Shrewsbu ry, and two by our countryman Mr Telford, the engi neer.
The centre arch of the bridge in Blenheim Park, is 10l ft. Gin. span.
In 1762, a single arch was built upon the river Tees, at \Vinstone in Yorkshire, from a design of Sir Thomas Robinson, the span of which is 108 feet 9 inches.
A very fine bridge has been lately erected at Ferry Bridge, in the same county, upon the river Ouse : it consists of three arches, the centre one 65 feet span, the width within the parapets 28 feet 6 inches.
In South Wales, the bridge over the river Taaf, near Llantrissart, in Glamorganshire, is justly celebrated, both on account of its great span, and the singular cir cumstances which attended its construction. In 1746, William Edwards, a country mason, undertook to build a bridge at that place. He built one of three arches, and it was allowed to be well executed; but, being in a mountainous district, the torrents sometimes rise hasti ly to a height which must appear incredible to the inha bitants of flat countries. One instance of this sort hap pened after this bridge had stood about two years and a half, when the torrent carried along with it trees, brush wood, hay, and whatever of this kind lay in its way : these were entangled in the arches, and, causing the water suddenly to create a great head, the bridge was swept away. As William Edwards had given security to main ta,in.tlie bridge for scyen years, he immediately set about rebuilding it ; but, in order to avoid future injuries from similar torrents, he constructed one arch, the segment of a circle of which the chord line was 140 feet, and the versed sine 35 feet. The arch was finished, but had not received the parapets, when the weight pressed in the haunches, raised up the crown, and destroyed the arch. This was in 1751. But Edwards, pos sessed of an uncommon degree of fortitude, resolved to rebuild the arch of the same dimensions; and it appears he took his measures prudently; for we have been in formed, by that excellent and respectable engineer Mr Jessop, who was then a clerk with Mr Smeaton, that Mr Edwards consulted that eminent man with respect to re building this large arch. Mr Jessop does not recollect
the advice which Mr Smeaton gave, but the bridge was rebuilt in 1755; the chord line and versed sine are the same as before, and the width across is eleven feet: in each haunch or spandrel there are three cylindrical arches quite across the bridge; the lowest is nine feet, the middle six feet, and the uppermost three feet dia meter. These, to avoid weight, are of course left hol low; and Mr Evans, a native of Wales, who was after wards chief engineer to the Royal Canal in Ireland, in formed Mr Jessop, that, in addition to the cylinders be ing left hollow, the spaces between them were filled up with charcoal. From the steepness of the ascent on each side, and the narrowness across, this bridge is more re markable as an effort of art than for the accommodation it affords.
Of late years, the building of bridges has been carried to a very great extent in Scotland. Upon the river Te viot, immediately above its junction with the Tweed, a very handsome stone bridge of three arches has been constructed from a design, and under the direction of Mr Elliot, an architect resident in Kelso. The middle arch is 65 feet span, and rises 17 feet; the arches are segments of circles, and the width over the parapets is 23 feet. There are coupled columns over the piers, which are quite insulated ; and the points of the piers are in the shape of Gothic arches. It was begun in 1794, and finished in 1795. About 4 years after the completion of this bridge, another very elegant one was constructed at Kelso, from a design of Mr Rennie, an eminent engineer. It is situated immediately be low the confluence of the Teviot with the Tweed. It consists of 5 arches, each of 73 feet span, and 21 feet rise; they are of an elliptical form, and the road over them is level. Over each pier, and upon each abut ment, are two small columns, and an entablature runs along the whole of the bridge. The columns are not in sulated, being .7.z. columns only ; the points of the piers are semicircular ; the width over the parapets 26 feet. It was begun in 1799, and finished in 1803. The characters of those two bridges being rather gentle than bold, ac cord well with the beautiful scenery of the adjacent banks of those two fine rivers.