On Draining. 



51 



If, therefore, we draw off effectually and constantly the bottom 

 water from beneath the clay, and from its substance, as far as it 

 admits of percolation, and by some other means provide a vent 

 for the upper water, which needs no more than this facility to 

 run freely, there seems good reason to suppose that the object 

 may be completely attained, and that we shall remove the mois- 

 ture from both portions as effectually as its quantity and the 

 substances will permit. Acting upon this view, then, after due 

 consideration, I determined to combine with the fundamental 4- 

 feet drains^ a system of auxiliary ones of much less depth, which 

 should do their work above, and contribute their share to the 

 wholesome discharge, while the under current from their more 

 subterranean neighbours should be steadily performing their 

 more difficult duty. 



I accomplished this by placing my 4-feet drains at a distance 

 of from 18 to 20 yards apart, and then leading others into them 

 sunk only to about 2 feet beneath the surface (which appeared, 

 upon consideration, to be sufficiently below any conceivable 

 depth of cultivation), and laying these at a distance from each 

 other of 8 yards. These latter are laid at an acute angle with 

 the main drains, and at their mouths are either gradually sloped 

 downwards to the lower level, or have a few loose stones placed in 

 the small interval between the two, sufficient to ensure the per- 

 pendicular descent of the upper stream through that space ; which 

 can never exceed, or indeed strictly equal, the additional 2 feet. 



The result surpassed, and has continued to surpass, my most 

 sanguine anticipations. When I first tried the plan I was drain- 

 ing a small grass field, containing much of the usual yellow clay, 

 and so wet that at one end of it there was a spot permanently 

 supporting a small bed of the Caltha palustris, or marsh mari- 

 gold, which it is well known grows only in genuine swamp, 

 where it can enjoy standing water on the surface. The follow- 

 ing little diagram will show more clearly the precise form and 

 nature of the case. 



Fig. 1. 



A EI G B 









X 





/ \ 







F K H 





C D 



The deep drains had been laid in this case 16 yards apart, 



E 2 



