FOR GREAT BRITAIN AND IRELAND. 41 



required conditions of tranquillity may be briefly summed 

 up in the few following words : sufficient shelter from 

 external disturbance, and adequate internal capacity for 

 tJie subsidence of such amount of undulation as cannot be 

 excluded. 



In a good natural harbour we find the principles of 

 shelter and tranquillity made evident to us by an elaborate 

 system of successive points or breaks, each followed by an 

 expanding area, which allows the undulation of the water 

 to spread, after its violence has been broken by the 

 preceding point. 



It is manifest that we cannot in an artificial harbour 

 adopt that irregularity of outline which, by offering a long 

 succession of points and bays to the action of the advancing 

 swell, gradually dissipates and pacifies the disturbance of 

 the ocean, but we can nevertheless adopt the principles 

 which nature inculcates, and show their application to 

 artificial harbours as far as the extent of any proposed 

 works will permit. 



As an example of a good natural harbour, the writer 

 has selected that of Dartmouth, as it furnishes us with 

 instances of those prominent features in which reside the 

 principles of shelter and tranquillity, and to which we will 

 now give our attention in the chart of that port. 



We have, outside the entrance, various rocks, both islet, 

 smaller insulated, and sunken, either above or below the 

 water, the large rock or islet known as the Mewstone, 

 125 ft. high, the Verticles, Bear Tail, and the Froward 

 Points, on the east, with Combe Point and rocks, &c., on 

 the west side, which, when the wind is either to the east- 

 ward or westward of south, serve to break the force of the 

 waves and much smoothen the water ; but in a southerly 

 gale, with which we have now to deal, being the point 



