Chap. VIII.

BRITAIN.

459

The cofferdams, though much smaller, were constructed in a similar manner to those oiLondon Bridge ; a double row of piles, diagonally braced and firmly bolted together, con-fined the clay and puddle, which kept out the water during the progress of the works.

O O O

Fig. 457.

STAINES bridge; cofferdams,

Under the piers piles w’ere driven, as shown in the plan, which were crossed with strongtimbers, and planked over for the footings of the piers ; a row of sheet piling was driven

STAINES BRIDGE ; ARCH AND ABUTMENT.

Fig . 45S.

all around at the toe or outside of the planking, to maintain the solidity of this portion, ofthe structure.

Fig. 459.

SECTION OF ARCHES.