Book III. EMBANKING. 645 



other rods added at the joint when the distance requires them. In boring through a 

 bank of the hardest clay, two men will work through from thirty to forty feet in a day 

 provided there is no interruption from hard stones, which will require the chisel to be 

 fixed on m place of the shell, and longer time to work through. If the length to be 

 bored through is considerable, or longer than the whole length of the rods, a pit must be 

 sunk upon the line, down to the hole, for placing the frame when removed, and the 

 operation carried on as before. 



Chap. II. 



Of Embanking and otherwise j)rotecting Lands from the Overflowing or Encrqachment of 



Rivers or the Sea. 



3997. Lands adjoining rivers or the sea, are frequently subject to be overflowed, or 

 washed away, or to be injured by the course of rivers being changed during great floods. 

 The subject of this chapter therefore embraces that of embanking and guarding the banks 

 of rivers. 



Sect. I. Of Embanking Lands from Rivers or the Sea. 



3998. The great value of alluvial soil to the agriculturist, no doubt, gave rise to the 

 invention of banks, or other barriers, to protect soils from the overflowing of their accom- 

 panying rivers. The civilized nations of the highest antiquity were chiefly inhabitants of 

 valleys and alluvial plains; the soil, moisture, and warmth of which, by enlarging the 

 parts, and ameliorating the fruits of the vegetable kingdom, afforded to man better nou- 

 rishment at less labor than could be obtained in hilly districts. The country of Paradise, 

 and around Babylon, was flat, and the soil saponaceous clay, occasionally overflowed by 

 the Euphrates. The inhabited part of Egypt was also entirely of this descriptioh. 

 Historians inform us, that embankments were first used by the Babylonians and Egyp- 

 tians, very little by the Greeks, and a good deal by the Romans, who embanked the 

 Tiber near Romej and the Po for many stadia from its embouchure. The latter is 

 perhaps one of the most singular cases of embankment in the world. 



3999. The oldest embankment in England is that of Romney Marsh, as to the origin 

 of which, Dugdal'e remarks, " there is no testimony left to us from any record or 

 historian." [History of Embanking and Draining.) It is conjectured to have been the 

 work of the Romans, as well as the banks on each side of the Thames, for several miles 

 above London, which protect from floods and spring tides, several thousand acres of the 

 richest garden ground in the neighborhood of the metropolis. The commencement of 

 modern embankments in England took place about the middle of the seventeenth century, 

 under Cromwell. In the space of a few years previously to 1651, 425,000 acres offers, 

 morasses, or overflowed muddy lands, were recovered in Lincolnshire, Cambridgeshire, 

 Hampshire, and Kent; and let at from 25. 6d. to 30s. an acre. (Harte's Essays, p. 54., 2d 

 edit.) Vermuyden, a Fleming by birth, and a colonel of horse under Cromwell, who 

 had served in Germany during the thirty years' war, was the principal undertaker of 

 these works. 



4000. Very littU has been ivritten on the subject of embankments, as a separate branch 

 of art, by British authors. Dugdale's work is entirely historical and topographical.- 

 But the writings of Smeaton, Young, Gregory, &c., contain the general principles ota 

 which is founded the art of embanking, and every other operation connected with water,- 

 and Beatson, in Communication to Board of Agriculture. Dr. Anderson, Marshal, and 

 some others, have written on the practice of the art. The works of this sort constructed 

 in our own times will be found described in The Agricultural Reports of the maritime 

 fcourtties, especially of Lincolnshire, by Arthur Young. We shall first submit sonle 

 general remarks on the principles of designing embankments, and next describe the prin- 

 cipal kinds of banks with their application. 



StJBSECT. 1. General Principles of designing Embankments. 



4001. The theory of embanking. Marshal observes, is beautifully simple. Th6 out- 

 Ward waters having been resisted by a line of embankment, and having receded, those 

 that have cbllected internally are enabled, by theit- own weight, to open a valve, sVhich is 

 placed in the foot of the bank, and effect their escape : thus securing the embanked 

 lands from inundation, though beset on every side with water. 



4002. The pressure of still ivater against the sides of the vessel containing it,- being as 

 its depth, it follows, that a bank of afiy material whatever, impervious to wa:ter, whose 

 section is a right angled triangle, and the height of whose perpendicular side is equal to 

 that of the tvatcr it is to dam in, will balaiice or resist this water, whatever may be the 



Tt 3 



