114 NOTES ON DOCKS AND DOCK CONSTRUCTION. 



The blocks were lifted by two barges fitted for the purpose 

 with a suitable stage and winches, suspension bars were passed 

 down through holes left in the concrete, the ends of the bars 

 entered oblong holes in cast-iron girders placed beneath the 

 blocks, and by turning a quarter round held securely. Hori- 

 zontal shafts were left in the bottom of the blocks for the beams 

 to be put in at low water, and they were withdrawn after the 

 blocks were set (Fig. 74). 



SECTION OF QUAY WALL, SHOWING BAGS 

 FiO. 72. 



->e 75-. 



SECTION OF QUAY WALL. SHOWING BLOCKS 

 FIG. 73. 



The barges were placed over the blocks an hour or two 

 before high water, the lifting bars were then secured to the 

 cross-heads and the chains strained by the winches until the 

 blocks were nearly lifted ; the tide then completed the lifting. 



Above low- water level the work was constructed of heavy 

 rubble limestone masonry, set in lias-lime mortar, the face being 

 set in Roman cement for G inches in, and the whole coped with 

 limestone blocks 1G inches thick. 1 



M.r.I.C.i:., vol. xliv. i. 138. 



