148 NOTES ON DOCKS AND DOCK CONSTRUCTION. 



350 tons. When placed in position, it completed at one opera- 

 tion 12 feet of quay wall up to the level of ordinary low water. 



The outer face of 

 the block was formed 

 of limestone set in 

 mortar composed of 

 4 parts of sand to 1 

 of Portland cement. 

 The hearting of the 

 block consisted of 

 stones weighing from 

 2 tons downwards, 

 as they came from 

 the quarry, and 

 placed not on their 

 flat beds but on their 

 ends, or on their 

 edges, and bonded in 

 every direction with- 

 out any regular 

 coursing. Every in- 

 terval was filled up with concrete, into which smaller stones 

 were rammed to form a compact mass. 



Sp_rings 



CROSS SECTION 



FTQ. 129. 



FRONT ELEVATION 

 FIG. 130. 



That nothing could exceed the soundness of this work was 

 proved whenever a mass was broken off, which was done with 



