200 Proceedinfjs of the Royal Irhli Academy. 



and sea walls. This damage was not due to the direct force of the 

 "waves, bnt to other circumstances. In this county nearly all the 

 piers and walls have vertical or nearly vertical faces, and at the time 

 mentioned, on account of the greater height of the water, these faces 

 caused waves to rise, that fell on and behind the piers, thus removing 

 the coping stones, and in places breaking the structures. In some 

 places the sea walls were similarly injured, while in others the water 

 flowing over the walls cut away the backing, and gradually cut out 

 breaches from the inside to the outside. 



On January 3, 1877, there was on the east coast a very high tide, 

 which along the Wicklow coast was accompanied by very moderate 

 wind.^^ This did considerable damage to the Dublin and Wicklow 

 Eailway between Greystones and "VYicklow ; not so much by the direct 

 force of the waves as by their height, they flowing over the line, and 

 the overflow cutting into the land side of the embankment, thus gra- 

 dually eating out the breaches. In no place did a breach commence 

 at the outside. ^^ This tide did not cause a "full" of the beach,, 

 although it pushed the margin higher and more inland than formerly. 

 Between Newcastle and the Wicklow Chemical "Works it encroached,, 

 in places, as much as three yards, into the Murrough {anglice sea 

 plain) ; and the beach after the tide presented a gradual slope, having 

 shingle and gravel to the margin of the old beach with fine sand in 

 the new portion. Elsewhere along the east coast of Wicklow and 

 "Wexford this high tide did little damage. It invaded kitchen mid- 

 dens and such like accumulations in the vicinity of the towns, and 

 floated out vast numbers of bottle corks, which in all cases were car- 

 ried northward by the "flow" and stranded along the margin of the 

 full tide. 



During the last six years various experiments were made during the 

 different stages of the tide, while the wind was blowing in different 

 directions, as also when "ground swells" were coming in, to test the 

 travelling of the beach, and also to discover what caused the ' ' cutting 

 out" of the beaches, and their filling in with white quartz pebbles 

 about the size of hen eggs. The effects of each wave were noted ; 

 these, of course, cannot now be described in detail ; we shall give only 

 the general conclusions arrived at in regard to this portion of the east 

 coast. "We cannot do the same for the coast between Carnsore and 

 the Hook, as the " counter-tides" there cause so many complications. 



^- At KingstoATn Pier, Co. Dublin, the wind was from the east at 8 a.m., with 

 a force of 7, and veered to the S. S. E. bj' 6 p. m., gradually falling to a force 

 of -3. 



13 This nearly always is the cause of bi'eaches in the steep-faced embankments 

 so general in Ireland to protect the different intakes ; they all fail from the water 

 topping them and breaching them behind. 



