190 On Draining. 



be more quickly and uniformly laid, and they give less inter- 

 ruption to water than the ragged edges of stone. Sod, or 

 turf drains also, are not filled ( I3 4) ; nor the clay pipe 

 drains ( I3 *y. These last, however, are better calculated for 

 small aqueducts for the conveyance of water, than for 

 draining land ; as when finished, the water can have no ac- 

 cess into them from without. 



5. The materials for partially filling drains are numerous ; 

 as, small stones, which answer for a considerable time, pro- 

 vided the drain be sufficiently wide at bottom, if stones to 

 the depth of at least two feet are used, and they are proper- 

 ly covered ; bricks or tiles, which are sometimes expressly 

 made for the purpose of draining, and are exempted from 

 duty on that account; turf or sods, which many recommend 

 in preference to any other substance ( I3 5J, and it certainly 

 has the advantage of cheapness ; wood, particularly old 

 thorns, cut into billets, which are well calculated for soft 

 or peaty soils, that are unable to bear the weight or pressure 

 of stone; green bushes, not in leaf, (in some situations 

 green willow is known to have lasted for ages)( 134 ); 

 black-thorn, which is a favourite material in Essex ; heath or 

 ling, which has been found a durable substance ; fern, furze, 

 or broom ; and where the drain is small, and better mate- 

 rials cannot be had, even straw, either loose, or twisted into 

 ropes as thick as a man's leg, The durability of the mate- 

 rials, at the same time, is of no less consequence in clayey 

 soils, than the probability of having a sufficient opening for 

 the water to flow through ; for clay sometimes forms an arch 

 over these materials, capable of supporting the incumbent 

 soil, and leaving a clear passage for the water below when 

 they decay. The materials must be covered with loose straw, 

 stubble, fern, rushes or turf, before the mould is thrown in. 

 The drains should be filled up as soon as possible after they 

 are ready for that purpose, and by the most careful of the 

 workmen. They should at any rate be completed before 

 winter, for if exposed to frost, they are apt to crumble down. 



6. When the soil is very wet, it will be necessary to cut 

 the small drains near each other ; from forty to fifty feet 

 distant in common soil, and from twenty to thirty feet in the 

 more stubborn ( l35 ). But deep and large ditches must be 

 cut around wet fields ( l36 ), into which the water, from the 

 smaller drains, is to be conveyed. 



7. When done with common skill and attention, drains 

 will last for twenty, twenty-five or thirty years, and in many 

 cases they have endured much longer. Indeed, & drain 



