Supplement to ''Nature," April 24, 1902. 



in securing such valuable sites from injury, and in forming 

 and preserving promenades in front of them ; and where 

 low-lying or reclaimed lands, extending a considerable 

 distance inland, are protected by sea banks, it is very 

 important that these barriers against extensive inunda- 

 tions should be efficiently maintained. In places, how- 

 ever, where long stretches of agricultural land, well above 

 sea-level, bordering the sea-coast are subject to gradual 

 erosion, the cost of adequately protective works would 

 amount to more than the value of the land lost. 



The author has for many years taken an interest in 

 the changes taking place along the coasts of England, 

 and the results of the various means adopted at different 

 places for their protection ; and his researches into 

 records and observations of littoral drift, the action of 

 waves and tides, sea-coast protection, and shingle-banks 

 and sand beaches have formed the subjects of papers 

 read at the Institution of Civil Engineers and meetings 

 of the British Association, and articles contributed to 

 The Engineer and this Journal, which have been collected 

 together to form the present book. The subjects are 

 dealt with under three general heads, namely, (ij 

 " Destruction," (2; " Littoral Drift," and (3) " Protection." 

 After a short introductory chapter, the first head is con- 

 sidered in a single chapter on '' The Action of .Shore 

 Waves " ; the second head forms the title and the subject 

 of the following chapter ; whilst the protection of the sea- 

 coast is dealt with in three chapters, two relating to sea- 

 walls and the third to groynes. These matters, however, 

 occupy barely more than one-third of the book, and the 

 remainder of the volume is taken up with an inordinately 

 long chapter of above two hundred pages, giving details 

 of the south, east, and west coasts of England, and a com- 

 paratively short chapter on the coasts of northern France, 

 Belgium and Holland. These two last chapters con- 

 stitute an elaborate compilation of facts concerning the 

 sea-coasts referred to, collected from various publications, 

 including naturally the reports and numerous data ob- 

 tained l)y the Coast Erosion Committee of the British 

 .\ssociation, and also the author's own observations, which 

 should prove useful for reference ; but the main interest 

 is comprised in the earlier portion of the book, which 

 embraces the chief object of its publication. 



In the chapter on the action of shore waves, the 

 author propounds his theory that the main agent of the 

 littoral drift observed along our coasts is tidal action, 

 and that storm waves are only au.\iliary agents of quite 

 minor importance ; and he restates this view with greater 

 emphasis, as an established fact, towards the close of 

 the following chapter, on littoral drift, in these words 

 (P- 75):— 



" .■\s already mentioned, the agent which is instru- 

 mental in building up shingle into banks and transport- 

 ing it along the coast is the tide, which accomplishes 

 this by means of the waves which are for ever breaking 

 on the beach as the tide rises and falls. The formation 

 and action of tidal shore wavelets has been already 

 described in the chapter on wave-action. These wave- 

 lets, aided by the flood current, lift up and carry forward 

 any coarse sand, loose stones, or other material with 

 which they come in contact, and leave some portion of 

 them stranded at the highest point on the beach to which 

 the tide of the day reaches." 



In a paper on " Littoral Drift," read at the Institution 

 NO. 1695, VOL. 65] 



of Civil Engineers in 1896, Mr. Wheeler enunciated this 

 theory, and m the discussion which followed, remark- 

 able unanimity was manifested by the speakers in dissent- 

 ing wholly from this view ; and it may reasonably be 

 surmised that the author hopes that acceptance of his 

 theory, which was on that occasion denied him by the 

 persons most conversant with the subject, may, when 

 brought forward in the sort of authoritative form of a 

 book, be granted him by the general public. His notion 

 of the power of tidal action is evidently in some measuie 

 due to his assumption that the tidal wave is a wave of 

 translation, with the entire body of water composing it 

 in motion throughout its whole depth ; and he does not 

 realise that this would involve a continuous movement 

 of the sea in one direction, at the rate of progression of 

 the tidal wave, which in the Pacific Ocean, the cradle of 

 the tides, amounts to about loou miles an hour, and 

 even in the English Channel reaches about 55 miles an 

 hour ; whilst the clashing together, off the mouth of the 

 Thames, of two of these waves of translation coming 

 from opposite directions would be a remarkable sight. 

 The author, moreover, in attributing littoral drift to the 

 action of the wavelets of the flood tide along the shore, 

 appears to ignore the reverse action of the ebb; though 

 in referring to the effect of tidal currents on submerged 

 sand-beds in channels, he points out that their "move- 

 ment is one of oscillation and not transportation." A 

 great number of instances might l^e cited of littoral 

 currents and littoral drift which, in the absence of a 

 tide, could not possibly be attributed to tidal action, as, 

 for e.\ample, the littoral movement across the face of the 

 delta of the Mississippi in the almost tideless Gulf of 

 Mexico, the drift which occurs in various places along 

 the shores of the Mediterranean, and the littoral current 

 which diverts towards the south the alluvium issuing 

 from the mouths of the Danube in the Black Sea. The 

 author tries to strengthen his contention as to the para- 

 mount effect of the flood tide by ascribing wind waves, 

 the power and influence of which are extended landwards 

 by the increased depth at high water, to tidal action. 

 Thus under the heading of " Tidal Waves " he says :— 



" In the great majority of cases the waves which affect 

 beaches, cliffs, and sea-walls are those which occur when 

 the rise of the tide affords the necessary depth of water 

 for their formation. . . . The maximum effect due to the 

 tidal wave is felt at the time of high spring tides, when 

 accompanied by heavy on- shore gales." 



Further on also the following passage occurs :— 



"Even when the depth of water in front of a sea- 

 wall or cliff is only that due to the rise of tide, water 

 from waves that break is thrown to very great heights. 

 Thus at Hastings, where the beach at the foot of the 

 sea-wall is dry at low water, and the depth of the water 

 is only that due to a rise of 15 feet at high water, during 

 a heavy gale in the winter of 1898 the broken water was 

 thrown as high as the top of a large hotel, as shown in 

 the frontispiece, and shingle was lifted oft' the beach 

 and carried across the promenade into the bedrooms of 

 the houses fronting the sea. At Peterhead, as already 

 mentioned, the water due to a rise of tide on the fore- 

 shore of only 7 or 8 feet has been known to strike the 

 wall with such force as to be thrown upwards 100 feet." 



It is certain that the inhabitants of Hastings will have 

 attributed the striking phenomenon illustrated in the book 



