Engineering Wonders of the World
Volume I

THE THAMES TUNNEL. 183 MAP OF EAST LONDON SHOWING SITE OF TUNNEL WORKS. carry the matter through. The company im- mediately engaged engineers to make sound- ings along the line of the proposed tunnel. The report submitted by them set forth that under the river extended a stratum of blue clay sufficiently deep to ensure the safety of the tunnel. Encouraged by this report, the directors appointed Mr. Brunel as company engineer, at a salary of £1,000 a year, and the promise of £5,000 when the tunnel should have pene- trated fifty feet from the embankments ; to which sum would be added a second £5,000 as soon as the first toll charge should be paid by the public. On February 16, 1825, workmen began to clear a space on the Rotherhithe shore, fifty yards from the water’s edge, for the erection of a brick caisson, 50 feet in diameter and The Shaft Caisson. rather more than 40 feet high. Short piles were driven into the ground to form a circle, and on them were laid wedges and a circular curb of iron supporting a wooden curb. This foundation was levelled with the greatest care, ready for the super- structure, the first brick of which was laid by the chairman of the company on the second day of March. Church bells rang merrily ; a couple of hundred people feasted ; large crowds shouted success to the undertaking. A temporary wall of bricks without mortar was built to a height of seven feet to secure an even bearing for the caisson. Though a dead weight of some 190 tons was superimposed in this manner, the settlement of the curb did not exceed one-sixteenth of an inch at any point. The workmen then removed the loose