Progress of the work.1881 the bottom heading commenced, we also commenced the tunnel proper in the upper heading, though the lowering had made this heading neither a top nor a bottom heading, but placed it some little distance above the centre of the tunnel.
At Sea-Wall Shaft we had commenced the tunnel itself, and the length of brick arch turned at this side of the river on the 1st January, 1881, was 93 feet.
We were also driving a bottom heading at the new levels, i.e., about 19 feet 6 inches below the old heading.
At a distance of 262 feet westwards of the Sea-Wall Shaft, we commenced on December 20th, 1880, a break-up to enable us to begin the tunnel proper at a second point. This was called ‘Sea-Wall Break-up No. 1.’ At a further distance of 200 feet from ‘No. 1 Break-up,’ we commenced on January 10th, 1881, ‘Break-up No. 2;’ and at a still further distance of 168 feet, on February 6th, 1881, ‘Break-up No. 3.’
At the end of April, 1881, the break-up length of brickwork was completed in No. 3 Break-up, and two lengths were turned, one at each end of it; the bricklayers were at work, and had nearly completed the second length east of the break-up, when suddenly the water burst in from the roof of the tunnel, and drove the bricklayers for a time away from their scaffold. This was a more serious difficulty than any we had hitherto met with, as it was salt water that came into the tunnel, and it