162 



HARBOUR CONSTRUCTION. 



In order to show the correspondence between the results 

 of calculation by the formula and the actual observations, Mr. 

 Stevenson gives the following table, which contains averages of 

 the observations at the places named. 



The number of observations made was very great, those for 

 Buckie alone being upwards of 2000. 



The results marked thus * were derived from a series of observations made 

 during the great gale of November, 1857. 



In these days of steam, when tugs are available at most 

 ports, the form and general arrangement of entrances, from 

 a nautical point of view, is not of such vital importance as it 

 used to be before such facilities existed ; nevertheless, in a gale 

 of wind hawsers cannot always be trusted, and there can be 

 no doubt that entrances should, where possible, be so designed 

 that vessels under sail could either take a harbour or leave it 

 without such help. 



In the case of harbours frequented by fishing fleets, the 

 subject is one of paramount importance. 



Considerable difference of opinion exists as to whether the 



