DOCK GATES. 



233 



timber was attached to the iron heel-post ; this piece of timber 

 closes against a corresponding vertical projection on the 

 stonework about 8 inches wide, and polished from top to 

 bottom. 



The gate thus clears the circle of the hollow quoin, except 

 in the line of thrust, which is communicated to the wall by the 

 interposition and accurate fitting of a piece of timber about 



FIG. 219. 



DETAILS OF COLLAR 



FIG. 222. 



8 or 9 inches wide. The arrangement of these timbers is shown 

 in Figs. 221, 222. 



To relieve the friction between the gate-post and the quoin, 1 

 the pivots are placed a little out of the centre, so that immedi- 

 ately the leaf is moved it clears the hollow quoin. A difficulty 

 attaching to this arrangement is that a space is left between 



1 M.P.LO.R, vol. Ixii. p. 29. 



