Reme7vs — Binstol and its Environs. 87 



If the wind and tidal actions are proceeding in contrary directions, 

 the maximum power of the wind-waves seems to be exerted during 

 the ebb of the tide — especially that of spring-tide — when portions of 

 the bottom are rooted up at depths which are ordinarily undisturbed. 



Should continuous heavy gales blow from a direction oblique 

 to the tidal-wave, accumulations of detritus due to the wind-waves 

 will form at one side of bays, while other accumulations, due to the 

 tidal driftage, will be formed at the opposite side. 



All these accumulations are of slow growth, taking weeks to 

 form. A gale, however, of forty- eight hours' duration — especially 

 during spring-tides — from a direction coinciding with, or obliquely 

 coinciding, with that of the tidal current, will sweep them all away. 



One point, however, calls for notice here, namely, that the ac- 

 cumulations due to the wind waves cannot be dissipated until 

 those due to the tidal current are first removed — the latter replen- 

 ishing the former as fast as they are removed. 



In support of these conclusions, detailed observations on the 

 South-east Coast of Ireland were given at too great a length to be 

 reproduced here, and the author concluded by making the following 

 deductions : — 



First, That the driftage due to the incoming tidal currents is 

 always going on in deep water, and also more or less in shallow water. 



Second. The driftage due to wind-waves only occurs during gales, 

 and even then is only due to the waves that break on the shores. 



Third. That the wind-wave driftage might be prevented from 

 damaging a harbour if . a floating breakwater were made to cross 

 the direction from which storms proceed, for a fixed one would 

 most likely tend to cause the harbour to become silted up. 



I^ IE "VI IE ^W S 



Bristol and its Environs — Historical and Scientific. 8vo. 

 pp. 475. London and Bristol, 1875. Published under the Sanction 

 of the Local Executive Committee of the British Association. 



IF the British Association in its annual visits to our larger cities 

 and towns has much to answer for in the diffusion of what some 

 would term Scepticism, and others a spirit of rational inquiry, it is 

 certainly instrumental in bringing before the public a number of 

 facts, and in creating an interest and wholesome stimulus in scien- 

 tific work. 



The book entitled " Bristol and its Environs " is a praiseworthy 

 example of what may result from such stimulus, and if other local 

 executive committees follow the example, we may have in time a 

 valuable series of hand-books. 



The geological chapters in this work have been written by Messrs. 

 E. B. Tawney, W. W. Stoddart, and E. Tate, each of whom, apart 

 from other work, has done good service in adding to our knowledge 

 of the local geology. Few districts have indeed been the subject of 

 so many contributions to geological literature as the country around 

 Bristol ; and no city can be prouder of one who devoted so much of 



