Again the diving-bell was used, and the hole was found in the bed of the river. To stop it bags of clay, with hazel sticks, were employed; and so difficult was the task that three thousand bags were utilised in the process, and more than a month elapsed before the water was subdued. Two months more passed before the earth washed in was removed, and Brunel could examine the work.
He found it for the most part quite sound, though near the shield it had been shorn of half its thickness of bricks. The chain of the shield was snapped in twain, and irons belonging to the same apparatus had been forced into the earth.
The men now proceeded with their task, and exhibited a cool courage deserving of all praise. Earth and water frequently fell; foul gases pervaded the stifling air, and sometimes exploded, or catching fire, they would now and again dance over the water; and again and again labourers would be carried away insensible from the poisonous atmosphere. Complaints, such as skin eruptions, sickness, and headaches, were common. Yet, in spite of every difficulty, the men worked on in that damp and dripping and fœtid mine, haunted ever with the dread of another flood.
And it came. On the 12th of August, 1828, some fifteen months after the previous disaster, the ground bulged out, a large quantity fell, and a violent rush of water followed; one man being washed out of his cell to the wooden staging behind.
THE THAMES TUNNEL.
The flow was so great that Brunel ordered all to retire. The water rose so fast that when they had retreated a few feet it was up to their waists, and finally Brunel had to swim to the stairs, and the rush of water carried him up the shaft. Unhappily, about half-a-dozen lives were lost at this catastrophe, and those who were rescued—about a dozen in number—were extricated in an exhausted or fainting state. The roar of the water in the shaft made a deafening noise; the news soon spread, and the scene became very distressing as the relatives of the men arrived.
Once more the hole in the bed of the Thames had to be stopped. Down went the diving-bell, but it had to descend twice before the gap was discovered. It was a hole some seven feet long, and four thousand tons of earth, chiefly bags of clay, were used in filling it. Again the tunnel was entered, and again the intrepid engineer found the work sound.
But, alas, another difficulty had presented itself—one more difficult to conquer even than stopping up huge holes in the bed of the Thames. The tunnel was being cut by a Company, and its money had gone; nay, more, its confidence had well nigh gone also. Work could not proceed without money, and for seven years silence and desolation reigned in those unfinished halls beneath the river.
Then the Government agreed to advance money, and work was again commenced. But it proceeded very slowly, some weeks less than a foot being cut, during others again three feet nine inches. The ground was in fact a fluid mud, and the bed of the river had to be artificially formed before the excavation could proceed in comparative safety. Further, the tunnel was far deeper than any other work in the neighbourhood, and all the water drained there—a difficulty which was obviated by the construction of a shaft on the other side of the river.