MAY. 311 



necessary works in most cases : and this considera- 

 tion should influence him rather to extend his car- 

 rier, than, by shortening it, be forced to water fields 

 not so well adapted as others at a greater distance : 

 probably the winter watering may go on through 

 the whole line. 



2. When such a level is taken as I have de- 

 scribed, there is often found below it a great va- 

 riety of soils and circumstances ; usually a low flat 

 range of meadows, perhaps wet and boggy, by the 

 side of the old river, and adjoining, and above 

 them slopes of pasture, and arable, it may be dry, 

 gravelly, sandy fields on various angles of declivity; 

 bogs, ling moors, and in short, every sort of soil 

 and land ; so that the irrigator may choose what he 

 pleases to work upon. Here he must be instructed, 

 that the lands usually chosen for the first opera- 

 tions, are just those that ought to be the last, viz. 

 the low flat meadows by the river. These are 

 often improvable to a very high degree by drain- 

 ing and manuring with sand, gravel, earth, chalk, 

 marl, &c.; but they are by far the most ex- 

 pensive to irrigate, and when done, unless very 

 well executed indeed, yield the worst hay. They 

 are best watered, and in many cases, only to be 

 watered advantageously, by ploughing them 'into 

 broad and highly arched ridges ; the delivering 

 trenches to be on their crowns, and uie drains in 

 Xheir furrows. But the profit of irrigating dry 

 slopes of sand and gravel, &c. arid poor dry ling 

 moors, is immense ; the expence is comparatively 



S 4 trifling, 



