FOR GREA T BRITAIN AND IRELAND. 87 



11. Lowering the top of the protecting outside break- 

 water. 



12. Converting an open staging into a close quay. 



13. Lengthening a breakwater, so as to intercept a greater 

 portion of the waves from certain directions. 



These last notes are from the article on Harbours, by 

 Mr. T. Stevenson, in the Qth edition of the * Encyclopaedia 

 Britannica/ at present (1883) in progress of publication. 



CAPACITY OF OPEN HARBOURS. 



Mr. Stevenson says, that " For open harbours it is not 

 easy to give even a good approximation. Lieut. Calver 

 takes it at three vessels per acre for a well-sheltered 

 harbour of refuge." 



RAMSGATE, A TIDAL HARBOUR. 



Capacity for outer harbour, 6 vessels to the acre. 

 Capacity for inner harbour, 14 vessels to the acre. 



CAPACITY OF FISHING HARBOURS. 



In the Scotch fishing harbours the number of boats 

 varied from 85 to 115 per acre of basin, but in consequence 

 of the increase of size of boats from 80 to 90. At Newlyn, 

 in Cornwall, from 60 to 80. 



OF MATERIALS, MASONRY, ETC. 



TIMBER. 



The use of timber in piers and harbour works is of 

 remote antiquity, and were it not for its perishable 

 character it would be superior to all other material for 

 these purposes. 



