88 



THE BRITISH ISLES. 



rolled into the Sound with the southerly gales, often causing great damage. To 

 remedy this defect a breakwater, 5,100 feet in length, has been constructed 

 across its middle. This stupendous work was commenced in 1812 by Rennie, 

 and completed in 1846 at a cost of nearly £2,000,000 sterling. About two 

 million and a half tons of blocks of coarse marble have been employed in its 

 construction. It is continually requiring repairs, for during severe gales the 



Fig. 47. — Plymouth. 

 Scale 1 : 268,000. 



Miles. 



blocks composing it, notwithstanding their weighing between 60 and 80 tons, are 

 often forced from their positions, whilst the destructive work of the pholades, or 

 pittocks, is going on at all times, converting the solid rock into pumice-like masses. 

 More than once this barrier has been broken through by the sea, and it is on record 

 that a helpless vessel was washed over the breakwater by the infuriated waves, and 

 landed in the inner Sound.* Experts assert that the height of the breakwater 



* Cams, " England and Scotland in 1844." 



