576 MR. PALMER ON THE MOTIONS OF SHINGLE BEACHES. 



the additional extent of the beach on the east side occasioned by the heavy gales is 

 represented by the dotted lines. 



The plan of Dover harbour, in the same plate, represents the state of the beach in 

 June 1 833, after the wind had blown rather strong for a few days. (This is drawn 

 from a survey made by Mr. J. S. Tucker, of the Hydrographer's Office in the Ad- 

 miralty.) The dotted lines to the eastward of the piers represent the general out- 

 line of the addition to the former by the recent gales, which having formed a barrier 

 across the harbour's mouth, extended about seven hundred feet beyond it. 



Many very interesting facts might be mentioned concerning the effects produced 

 by the continued gales at various places on the coast, but I find that the description 

 of them in sufficient detail to make them useful would extend this paper much be- 

 yond the limits assigned : I, however, trust that a reference to two of the most 

 remarkable cases will be found sufficient to illustrate the principles attempted to be 

 explained. 



Section 7. 



The only natural power by which the channels through the beach are retained, is 

 the returning force of the water, which on this coast is generally scanty. And it is 

 obvious, that however judiciously that force may be employed, it is but remedial in 

 principle, and necessarily implies a previous evil. So long, therefore, as the cause 

 continues to act, the remedy is prevented, and the harbour becomes inaccessible 

 when protection is most required. 



If on inspection of the great bank recently thrown up at Dover (as represented 

 upon the plan), we imagine it to be dispersed over several miles of the sloping plane, 

 and assume the whole to be in continued and equable motion, it will immediately be 

 inferred, that the quantity that would be passing a given spot at one time would be 

 comparatively insignificant ; and hence, since we have no reason to suppose that 

 there will be a limit to the quantity, and since it has been shown that its motion can- 

 not be prevented, it follows that the great objects in view must be attained, first, by 

 securing permanently such accumulations as are necessary for the protection of land 

 from the action of the sea, or useful by their addition to its surface ; and secondly, 

 by facilitating and inciting the progressive motion of that superfluous quantity from 

 whence the evils complained of are derived : and therefore the uninterrupted and 

 permanent welfare of the numerous harbours which communicate with the sea, 

 through the extensive tract of the shingle beach, is dependent more on a system of 

 management along the coast, than upon particular devices adapted exclusively to 

 each separate case. 



18, Fludyer Street, Tfliitehall. 



