Hunt — On the Action of Waves on Sea-beaehes, 8fc. 247 



Opinions as to the Accumtilatiye and Destkuctite Action of Wates 

 ON Beach-shingle. 



Mr. CooDE. 



Mr. Kinahan. 



" It is known tliat shingle accumulates 

 upon any beacli with off-shore winds, 

 whilst it is carried off, or scoured away, 

 during on-shore winds, and more espe- 

 cially by the ground-sweU which follow's." 

 — C. 23. 



Mr. Palmer. 



"I watched for an opportunity of 

 witnessing that rate of succession which 

 exhibited the destructive and accumula- 

 tive actions in their smallest degrees; 

 and I observed that when ten breakers 

 arrived in one minute, the destructive 

 action was but just evinced ; and that 

 when only eight breakers arrived in the 

 same period, the pebbles began to accu- 

 mulate ; which facts harmonized with my 

 observations made at Sandgate and Folke- 

 stone, viz. that the difference between 

 the two actions was determined by the 

 rapidity in succession of the waves upon 

 the shore."— rraws. R. S., 1834, p. 571. 



" The ordinary wind- waves assist the 

 flow-tide currents when they are going 

 in the same, or nearly the same, direction 

 with those currents. If they strike the 

 beach at a right angle, or nearly so, they 

 pile it up, forming ' fuUs ' and ' storm- 

 beaches ' . . ." — Travelling of Sea 

 Beaches (loc. cit.), p. 3. 



Mr. Kinahan, writing of the east coast 

 of Ireland between Carnsore and Dalkey, 



says : — 



"W. and S. -W. winds generate 

 ground-swells, which usually cut out 

 the beaches." — Ibid. {loc. cit.), p. 4. 



(These winds are off-shore.) 



"Ground swells with E. winds some- 

 times seem to assist in filling in the 

 beaches, but with N.-E.. winds they 

 cut out." — Ibid. {loc. cit,), p. 5. 

 (These winds are on-shore.) 



Mr. CooDE. 



"The views here expressed" (Mr. 

 Palmer's) " are opposed to the con- 

 clusions arrived at from the Author's 

 observations on the Chesil Bank and else- 

 where. The rule, as far as one can be 

 formed from the number of waves in a 

 given time, appears to be, that seven, or 

 any less number of waves per minute, 

 indicate the destructive action, and nine, 

 or any greater number, the accumulative 

 action ; but no very precise rule can be 

 formed upon this basis." — C. 23, 



