Progress of the work—1885. in the ground where the Great Spring had been stopped back, had been of course producing a greater and greater pressure upon the brickwork, till the pressure had at last risen to 57¼ lbs. on the square inch. Under that pressure the bricks in the tunnel began to break, pieces flying off them with reports like pistol-shots, and the water shooting through the broken bricks quite across the tunnel.
Two of the largest of the pumps which had been fixed to deal with the Great Spring in the Old Shaft had been taken out before I left for South America, and only the 31-inch pump worked by a 60-inch beam-engine was left in that pit to deal with any extraordinary quantity of water which might find its way through the brickwork.
Mr. J. Clarke Hawkshaw had gone to South America with me, and had remained there when I returned. Sir John Hawkshaw was naturally extremely anxious about the state of the works, and when I had seen him, and heard what had occurred since I left. I visited the works and found them in a very serious, if not dangerous, condition, and I at once asked Sir John’s permission to take off the pressure. He was of opinion that our pumping-power was not sufficient, and that the water from the spring was coming in behind the work in greater volumes than we were able to pump.
Having, however, obtained his sanction to making the attempt, I broke out the pipe adjoining the sluice valve at the eastern end of the side-heading,