Book III. 



IRRIGATION* 



663 



the water to the longest corner of the panes, and sometimes taken out of different parts 

 of the trenches, to water some httle irregularities in the panes, which, without such assist- 

 ance, would not have any water upon them. There is a sluice (i) erected at the end of 

 one of the small mains, to force the water into the branch (reach adjoining!/), that being 

 the highest ground. 



4107. A vert/ complete piece of irrigation (Jig. 531.) was formed for the Duke of Bed- 



ford, by Smith, at Pristley. The water is supplied from a brook (a), to a main feeder 

 with various ramifications (b, h ^ the surface is formed into ridges (c, c), over which the 

 water flows, and is carried oif by the drains in their furrows {rf,rf;,to the main drains {e,e)f 

 and to the brook at different places (/,/,/)- There are bridges (g) over the main 

 feeders, small arches over the main discharging drains {h\ and three hatches (i). 



4108. As an example of catch-work loateringy we may refer to a case (Jig. 532.), give 



in a recent work by John Drown. (Treatise on Irrigation, 1817.) In this the field of 

 operations being on the steep side of a hill, a main carrier is led from the sluice (a), 

 directly across the declivity [h], and lateral feeders (c) taken out from it at regular dis- 

 tances. These feeders have stops of turf, at regular distances (rf), by which nieaf^s 

 the water is dispersed. After watering a space of from twenty to forty feet in breadth, it 



Uu4 



