20 HARBOUR CONSTRUCTION. 



"At that time the hurricane was still within the tropic, and 

 distant ten degrees of latitude. 



" As the storm approached the swell increased, breaking against 

 the southern shores with louder roar and greater grandeur, until the 

 evening of September 12, when the whirlwind storm, reaching 

 the Bermudas, set in there. When the storm had passed over the 

 Bermudas, the southern shore became calm, and the northern reefs, 

 in their turn, presented a white line of surge." 1 



It would be out of place were I, in this volume, to pursue 

 the subject of forecasting weather further. Much progress has 

 been made of late years in the science of meteorology, but it can 

 scarcely yet be called an exact science. 



The reader will, however, find much valuable information on 

 this subject contained in the book, to which I have already 

 referred, entitled "Weather," by the Hon. Kalph Abercromby 

 (Kegan Paul and Co.), which he cannot do better than peruse. 

 I have found it of much service, and am indebted to it for many 

 of the facts recorded in this chapter. 



Winds, apart from their action in forming waves, affect 

 harbours in other ways. 



Due attention must, for instance, be given to the direction of 

 prevailing gales in determining the position, direction, form, 

 and width of harbour entrances ; otherwise an entrance may be 

 so placed as to be difficult or dangerous for a vessel to take 

 during a gale, or it may form a trap for littoral drift. 



A badly designed entrance will often lead heavy seas into a 

 harbour, thereby causing a dangerous " run " and inconvenient 

 range. 



The usual sequence of winds should also be considered, in 

 order that, as far as possible, the convenience of vessels getting 

 to sea as soon as the wind has shifted into a more favourable 

 quarter may be provided for. 



The drift along the coast is, in the majorit} 7 " of cases, very 

 largely due to wind, and to the waves set up by its action. 

 The angle at which these impinge upon the shore will be found, 

 in most cases, to determine the direction of its travel, the 

 preponderance of drift, one way or the other, usually bearing 

 a very marked relation to the direction of prevailing winds. 



Drifts above the water-line, on sandy shores, proceed con- 

 currently with those caused by wind waves below such level ; 

 1 " Law of Storms and Variable Winds," chap. iv. p. 36. 



