Q18 AGRICULTURE. BOOK I. 



side next the sea with wood, such as the larch ( alone,) or any 

 other wood coated over with pitch and sharp sea-sand. Even 

 old sail-cloth or oil-cloth, pitched and sanded, and then neatly 

 laid on, will answer as completely as pavement during a cer- 

 tain time, although these materials will fail much sooner. Per- 

 haps in some cases it might be requisite to cover it with a me- 

 tallic substance, as sheet-lead, or tinned copper plates; or by 

 many other ways, at different rates of expense, and diverse de- 

 grees of duration. 



SECT. VI. OF THE EXPENSE OF MAKING EMBANKMENTS. 



Although the expense of embanking is considerable, it is far 

 from being so great as is generally imagined. It is, however, 

 impossible to mention any specific sum for this purpose, un- 

 less certain data were given; but, from the different calcula- 

 tions and estimates which I have made for various places in 

 Great Britain*, I find that a dike of earth covered with gravel 

 or sand, such as fig. 1. Plate 10. would cost from threepence to 

 eightpence per cubic yard; — such as are of a more steep slope, 

 say from thirty-five to forty-five degrees, and covered with 

 pavement, from sixpence to one shilling per cubic yard; the 



* Partly for my own information, and partly for proprietors, as Lord Keith, the 

 Earl of Selkirk, Earl of Galloway, &c. 



