TOULON DOCK. 



185 



The following are the finished dimensions of the dock : 



Ft. 

 401 

 421 

 110 

 86 



Length of coping level from head to face of inner caisson stop 



Ditto to face of outer caisson stop 



Centre width of dock at coping level 



bottom 



Width of floor 52 



Width of entrance at coping level ... 94 



bottom 82 



Depth of water over sill 34 



Total depth of entrance 37 



Depth of water over blocks 31 



Total depth in dock 37 



Coping above water level 2 



The total height of the caisson, viz. 62 feet 4 inches, was 

 divided into two distinct portions. The lower part, or bottom, 



. 170. 



to the level of the top of the air-chamber, was divided longitudi- 

 nally into 18 compartments by transverse water-tight bulk- 

 heads. The second portion, extending to the top of the caisson, 

 formed a large, uninterrupted chamber, within which was 

 constructed the invert and side walls of the dock, the weight of 

 which formed the load necessary for its submersion. 



In its construction, the caisson was divided into three parts : 

 (a) the caisson proper, forming the base of the structure ; (6) the 

 sides resting above the base to about 3 feet above the water 

 level ; and (c) the dam for closing the entrance. 



The base consists of outer walls, and top of iron plates, with 

 a large double girder extending round the whole structure. The 

 outer web of this girder was made solid, and the inner one open, 

 in order to admit of the masonry being more efficiently built in. 

 The length was divided by 17 transverse girders, extend- 

 ing the full width of the caisson, and the width by two 



