Submarine Appliances And Their Uses
Deep Sea Diving, &c., &c.

The following- section will serve to illustrate the procedure. The walls of the Cathedral having first been well grouted up by means of the “Greathead” grouting machine to fill all the cracks, a length of wall from 5ft. to 6ft. is attacked. A pit “ A ” is sunk, and by its means the old foundations are uncovered and the beech trees exposed. Water is then reached, and with the aid of ordinary exca- vation and light pumping the clay is re- moved and the peat bed uncovered. Pump- ing has then to cease. This Peat Bog, under the heavy weight of the building, was compressed, and although it is to-day 8ft. 6in. in thickness, it was in all probability at the outset 12ft. in thickness, resulting in a very serious and unequal subsidence, and which no doubt caused great anxiety to the original builders. i he water is allowed to rise to its normal level, and the work is continued by Diver. He excavates the peat beneath the wall, the length, as before stated, being 5ft. to 6ft., whilst the extent of the drift beneath the water and below the walls varies from 9ft. to 22ft. He carefully cuts down the peat to a vertical line, removing every particle from the surface of the gravel. So soon as this excavation is completed, jute bags filled with concrete in cement, ready mixed, are lowered down to him, and these he places side by side until the whole area is paved over with bags. These are then slit open with a knife to allow the material to be spread by the diver over the surface. Four such layers of bags are thus placed in position, and when it is remembered that the whole of the work, both of excavation and concreting, is done in absolute darkness and entirely by feeling, the greatest credit is due to Siebe, Gorman and Co. ’s diver for the care and zeal with which he carries out this arduous task. On every occasion of inspection under water by Mr. Pox,* he has expressed himself as fully satisfied with the work. When the four layers of bags have thus been placed in position, a sufficient length of time is allowed to elapse for the concrete to set, the inflow of water is checked, and the water in the hole pumped out. The work is then continued by ordinary masons and bricklayers up to the under- side of the original foundation, the beech trees are removed, and the Cathedral finally stands for all time on a solid and satisfactory foundation. * This well-known Civil Engineer, though well in the sixties, makes personal inspection of the under water work. 79