ON THE PROTECTION OF AGRICULTURAL LAND. 



An illustration of the abrading action of small rivers or streams 

 may be found whenever they traverse a flat alluvial tract of 

 country. If the velocity of the stream be sufficiently great 

 to abrade the banks, it will commence an attack at some vul- 

 nerable point where the soil is very soft. This soft bank soon 

 assumes a concave outline, round which the stream sweeps 

 and impinges with violence directly on the opposite bank, 

 which, in its turn, soon yields to the abrading action, and 

 another concavity is hollowed out in a direction opposite to that 

 first formed. In this way the river, deflected from bank to bank, 

 enlarges its bends and lengthens its course. But as the length 

 of its course increases, the gradient and velocity of the stream are 

 reduced, and its abrading power, which, as we have said, depends 

 on the velocity, may ultimately by successive bends be so dimi- 

 nished that the original destructive current becomes a placid 

 stream, incapable of making further violent inroads on the banks ; 

 and to this state of permanent conservation many of the tortuous, 

 sluggish rivers to be seen meandering through the flat meadow 

 lands of England have been brought, but the sluggishness of 

 such streams may have been attained at a considerable sacrifice 

 of valuable land. Perhaps the most notable instance, on a large 

 scale, inScotland, of a winding river is the Forth. The straight 

 distance from Stirling to Alloa is about 5 miles, which with a fall 

 of 13 feet between the two places gives a gradient of 2 feet 7 

 inches per mile, but following the course of the river the dis- 

 tance is about 10 miles, giving a gradient of about 1 foot 3 

 inches per mile, while the land occupied by the '* Links " or 

 " bends " amounts to nearly 500 acres unavailable for cultiva- 

 tion. In referring to this case, I do not wish in any way to 



