SETTLEMENT AND BOND. 



279 



Even in a blockyard, when blocks are stacked too high, or 

 without due care, the lowermost of them are sometimes fractured ; 

 and I have known ashlars of Bramley Fall stone to be broken in 

 the same way. Long blocks are, moreover, liable to " bridge " 

 local settlements, and thus allow the blocks below them to 

 become loose and fall away. 



From what has been said, it will be seen that all blocks 

 should be laid as "headers," alternate face-blocks being made 



no. 90. [ELEVATION] 



FJG. 91. [PLAN] 



shorter than the others, so as to give such transverse bond as 

 may be deemed necessary. 



The bond ordinarily adopted in breakwaters for horizontal 

 coursed work is shown in Figs. 90 and 91. 



Various expedients have been resorted to in order to prevent 

 the withdrawal of individual blocks, but ordinary dowelling or 

 joggling (Fig. 91) is perhaps as simple and effective as any. 



Joggles are usually made of fine, rich Portland cement 



