PART IV. AGRICULTURE. 211 



that building a perpendicular wall of good stone, against 

 broken abrupt shores, will niake them nearly as strong and 

 durable as the natural ones, which are composed of perpendi- 

 cular, solid rock. A case of this kind occurred at SeaclifF, 

 near Edinburgh. (See fig. 4.) 



Walls built thus are of great use in defending abrupt sea- 

 shores. They are not so generally applicable to rivers; be- 

 cause there, the water, in times of flood, requires room to 

 spread ; and this is the great use of sloping their banks ; — but 

 this mode, by confining it on every side, would only tend to 

 make it do more damage than before. There may be cases, 

 however, where it may be desirable to defend one part of the 

 banks of a river without sloping them, or to defend one bank 

 at the expence of that opposite ; and here it may be used with 

 propriety, — though piers properly made in such places are 

 often more complete, and always more economical. Between 

 these two kinds of banks, which are natural, art may contrive 

 one, which shall answer some of her purposes better than 

 either. 



3. In place of collecting such a quantity of earth or other ma- 

 terials as will be necessary to form a bank similar to fig. 1. or 3., 

 it may be more economical to make one such as fig. 6. ; the 

 side next the sea forming an angle with the base of 45 degrees. 



