GLASGOW DOCK. 



209 



tion of about 1 in 300, surrounded and covered to a depth of 

 18 inches with screened gravel. In order to prevent the pipes 

 choking with sand which worked in through the open joints, a 

 small wire rope with wire brush attached was carried through 

 each from the well to the extreme end, as the excavation pro- 

 ceeded. This arrangement of drainage pipes and method of 

 keeping them clear was successful in securing a well-dried 



SECTION ON LINE C D IN FIG. 196. 



Cafe 



E- 



k 



PLAN 



FIG. 196. 



surface on which to lay the bottom bed of concrete forming 

 the lowest section of the foundations for the floor and side 

 walls. 



The bottom bed of concrete shown in Figs. 197, 199, 200, is 

 12 inches thick at the centre, and 3 feet 2 inches at the sides, 

 and on this a brick-in-cement invert, 4 feet 2 inches in thick- 

 ness, was laid to a radius of 120 feet. On this invert was 

 placed an upper bed of concrete 4 feet 5 inches thick in the 

 centre, thinning out to 12 inches at the sides. The upper 

 surface was cambered 6 inches, and on this was laid the flooring 



P 



