3l6 MAY. 



tiling more is requisite than to cut trenches .of de- 

 livery, which operate by alternate watering, both 

 as deliverers and as drains. This is a point little 

 understood in watering through several districts I 

 have seen, and as it is a very important one, and 

 a branch of that diagonal system I have already ex- 

 plained with relation to the position of the fields, 

 it merits a short explanation. 



In the annexed Plate, the slope of the land from 

 A to B, is supposed regular, which, of course, 

 rarely happens in Nature, nor is it essential, as any 

 man who has common sense will see that inequali- 

 ties of surface, though they may break the uni- 

 formity of his lines, by causing a necessity of going 

 round hills or holes, yet will make no breach in the 

 principles which govern the irrigation. 



Here, it appears, that if water from the main 

 carrier, river, or ditch, 31, be let into the deliver- 

 ing trench, 32, and the stop, 33, be let down, the 

 water will flow over the division of the meadow 

 (or pane, as Mr. Boswell calls it) K The deliver- 

 ing trench, 34, then acts as a drain, and conducts 

 the water into the trench, 35, the. stop, 36, being 

 letdown; thence, of course, it overflows the pane 

 No. 2, and in like manner, successively, No. 3, 4, 

 and 5. If the step, 33, be drawn up, and the 

 stop, 37, let down, the panes 6, 7, 8, and 9, are 

 watered in the same way ; and soon by the stops 

 38 and 39, which will water the panes 10, 11 and 

 12; also 13 and 14: and the stop, 40, being let 

 down, and 41 drawn up, the pane, 30, will be 



watered. 



