AVONMOUTH LOCK. 



169 



of this lock is 600 feet, and between the outer and inner gates 

 454 feet ; this latter length is divided by a set of intermediate 



600.' j-" 



FIG. 146. 



gates into two compartments, the inner one being about 50 feet 

 longer than the outer one. 



The foundations consist of rubble masonry, varying from 



Lime Concrete covered 

 with Llandaff Pitching 

 about 2'.o"thick 



FIG. H7. 



100 to 120 feet wide, and from 5 to 6 feet deep; on this bed 

 of masonry the walls and inverts are built. The side walls 

 are constructed of rubble masonry faced with random-coursed 



