and of the intended Bridge. 6l 



The iron work of this bridge has fully juftified the idea of 

 making ufe of that metal ; for it is at this time as perfect as 

 when it was firft put up, except the cracking of fome of the 

 fmall pieces, owing to the giving way of the abutments of 

 ftone, which, it is to be regretted, were not made fufficiently 

 ftrong to oppofe the great mafs of alluvial earth, of which the 

 very high and deep adjoining banks are compofed ; for, if 

 thofe abutments had been fortunately built on the coal mea- 

 fures, no fuch flip could have taken place. 



The fecond iron bridge was built over the fame river, about 

 two miles above the former one, at a place called Buildwas ; 

 it was erected at the cxpenfe of the county of Salop, agreeably 

 to a plan, and under the direction, of Mr. Telford, who is 

 employed as furveyor of the public works of that county : it 

 was alio caft at Coalbrookdale in 1795 anc ^ ^19^- ^ confifts 

 of one arch 130 feet in the fpan, and rifes, from the fpringing 

 to the foffit of the arch, 27 feet. In this bridge, as it was 

 neceflary to keep the roadway as low as poflible, the principle 

 of the Schaffhaufen bridge is in fome degree adopted ; for 

 the outlide ribs are made to go up as high as the tops of the 

 railing; they are connected with the ribs that bear the co- 

 vering plates by means of pieces of iron, dovetailed in the 

 form of king-pofts. The plates which form the covering 

 over the lower ribs are caft with deep flanches, are laid clof'e 

 to each other, and form an arch of themfelves, fo that, al- 

 together, the bridge is compact and firm. The weight of 

 iron is 173 tons, 18^-cwt. Some fmaller bridges, and an 

 aqueduct at Longdon, (the firft made of iron over a navigable 

 canal,) have alfo been made under Mr. Telford's dire£tions, 

 in Shropfhire. 



The next bridge, on a large fcale, which was made of iron, 

 was that over the river Wear, at Monk-wearmouth, in the 

 county of Durham. This bridge is 236 feet in the fpan, and 

 the arch rifes only 34 feet : it is compofed of very fhort caft- 

 iron frames, which are connected together by bars of wrought 

 iron, and hollow tubes with flanches and fcrews ; the ribs are 

 covered with timber planking. The weight of caft iron ufed 

 in this bridge is 205 tons, hammered iron 55 tons. This 

 bridge was built under the direction, and chiefly at the 

 expenfe, of Rowland Burdon, efq. ; it was caft at the ma- 

 nufactory of Meflrs. Walkers, ot Rotherham, in Yorkfhire, 

 and does much honour to the projector and to the iron maf- 

 tcrs. It was a confiderable ftep in the practice of bridge 

 building, being nearly double the fpan of the arch of Build- 

 was, and confiderably more than double that of the centre 

 arch of Blackfriars bridge. This will, perhaps, appear raft 



to 



