At the age of twenty-three Telford at length quitted Eskdale, and visited Edinburgh with a view to obtain better employment. The splendid improvements then in progress in that city enlarged his field of observation, and enabled him to contemplate architecture as applied to the object of magnificence as well as utility; and he seems at this time to have devoted much attention both to the scientific study of architecture and to drawing. After remaining in Edinburgh two years, he removed to London, where he obtained employment upon the quadrangle of Somerset House, then erecting by Sir William Chambers, an engagement in which he states that he obtained much practical information. After this, in 1784, he was engaged to superintend the erection of a house for the resident commissioner at Portsmouth Dockyard, and for the next three years was occupied upon various buildings in this dockyard, which gave him good opportunities of becoming well acquainted with the construction of graving-docks, wharf walls, and other similar engineering works. Two or three years previous to this, Telford's good character and promising talent had secured for him the friendship of two families resident in his native district,--the Pasleys and the Johnstones,--and to their influence his early employment on important works is in some measure to be attributed. In 1787, having completed his engagements at Portsmouth, he was invited by Sir William Pulteney (a member of the Johnstone family) to take the superintendence of some alterations to be made in Shrewsbury Castle. Telford consequently removed to Shrewsbury, where he was employed to erect a new jail, completed in 1793, and was afterwards appointed county surveyor, in which office (retained by him until death) he had to design, and oversee the construction of, bridges and similar works. The first bridge which he designed and built was that over the Severn at Mont-fort, consisting of three elliptical stone arches, one of fifty-eight, and the others of fifty-five feet span. His next was the iron bridge over the Severn at Buildwas, which was the third iron bridge ever erected in Great Britain, the first being the Colebrookdale in Shropshire, built in the years 1777-9, and the second the Wearmouth,[38] erected between the years 1793-6. Telford's bridge over the Severn was erected in 1796, and consisted of a single arch of 130 feet span, formed of five cast iron ribs, and having a rise of only 14 feet; the width of the platform is 18 feet, and the total weight of iron in the bridge about 174 tons; it was constructed by the Coalbrookdale Ironmasters at a cost of 6,034_l._ Forty smaller bridges were erected in Shropshire under Telford's direction.