90 ON DRAINING. 



stopped with soil alone ; but it was also true tliat others, into 

 which the roots had worked, were free of earth. From all the 

 evidence that Mr. Parkes could collect on the spot, he was 

 disposed to attribute the stoppage bj roots to bad laying- of 

 the pipes by the farmer, and insufficient depth of drain in a 

 very foul piece of land. He laid a drain dee})ly in the same 

 soil, with pipes collar-jointed, and other drains, to test any 

 difference in future action and phenomena. 



Natvral aids to Dimnagc. — Besides the porosity of 

 soils, by which they receive and part with water more or less 

 readily according- to their openness or retentiveness, there 

 are other adjuncts or means auxiliary to its reception and 

 discharg-e. It has not occiu-red to me to excavate many 

 claj^-soils for drains, in which there are not perceptible what 

 experienced and observant drainers aptly call water-veins. 

 The clay is divided, as it were, into plates, masses opening- 

 or parting- from each other like the leaves of a book, between 

 which, thin as the vein is, an evident passag-e of water has 

 taken place. These parting-s may have been originally occa- 

 sioned by vertical cracks from the surface, which have never 

 entirely closed again, and so served to conduct away some 

 of the rain water to more porous and absorbent strata. It is 

 a matter of fact, that in all clays in which these water 

 veins occur in the g-reatest number, I have found drainag-e to 

 be effected the most speedily, and I practically use the per- 

 ception of their presence as some guide to the distance at 

 which I determine to place the drains from each other. 



But the most active and potent of the drainer's auxiliaries 

 is the common mining- earth or dew worm. The earliest 

 written notice which I have seen of the utility of the earth- 

 worm in drainag-e is to be found in Mr. Beart's article on 

 draining-,^ in every word of whose remarks I concur. Earth- 

 worms love moist but not wet soils ; they will bore down to, 

 but not into water; they multiply rapidly in land after 

 drainage, and prefer a deeply dried soil. 



On examining- with Mr. Thomas Hammond, of Penshurst, 

 Kent, part of a field which he had deeply drained, after long- 

 previous shallow drainage, we found that the worms had 

 greatly increased in number, and that their bores descended 

 quite to the level of the pipes. Many worm-bores are large 

 enough to receive the little finger, and it is possible that one 

 worm lias several bores for his family and refuge holes from 



' Journal, vol. iv. p. 212. 



