FOR GREA T BRITAIN AND IRELAND. 83 



decked-vessels not to mention our trawling and cod- 

 smacks it is quite clear that special arrangements are 

 required for their accommodation. In outside basins the 

 construction of a talus is a very doubtful advantage, for 

 although it may undoubtedly assist in the reduction of the 

 undulation, it may itself constitute an element of danger 

 in bad weather if a vessel should drive upon it, for in outer 

 harbours it is extremely difficult to keep any small sub- 

 stances in position as a coating. 



The violent action of the water holds the sand in 

 suspension, and deposits also the small shingle therewith 

 at the foot of the incline as the tide ebbs. On open 

 beaches especially, such as are frequently receiving acces- 

 sions of material from neighbouring cliffs, composed of 

 strata of sandstone of a friable character, and gravel, the 

 action of the water may be observed with much profit to 

 the engineer in reference to artificial beaches in harbours, 

 commonly known as hards, careening, or beaching places. 



On a beach constantly receiving accessions, as above 

 mentioned, the writer has observed that in the most 

 exposed positions the sand will not remain upon the slope, 

 but is removed or sifted out from the shingle by the 

 action of the waves ; and the boundary just below the line 

 of low water is so marked at some localties of great 

 exposure, that the appearance is as if the whole of the 

 shingle had been thrown on the upper side of a line by 

 the hands of man. 



Mr. Stevenson observes that a talus should be rough to 

 be efficient in reducing the height of the waves in a close 

 harbour, and that if smooth it is deprived of much of its 

 reductive power ; if however it be so placed in an outer 

 harbour that vessels are liable to be driven on it (and it 

 would be difficult to find a position where no such 



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