246 



Draining. 



Voi,.V. 



For the Farmers' Cabinet, 

 Draining. 



Mr. Editor, — That is, indeed, a novel 

 mode of draining which you describe, at page 

 2536 of the Cabinet, as Smith's of Deanston. 

 "What, to cut the drains down the slope in- 

 stead of across it, and carry them regularly 

 through the farm, without regard to subsoil 

 or topsoil, and to the amount of one hundred 

 miles on one farm! I suspect that Mr. 

 Smith does not depend wholly on farming for 

 a living; perhaps he is like my friend Searle 

 of Pitplace, who used to say, if it had not 

 been for Mister Searle, Farmer Searle would 

 have broken up before this. Assuredly this 

 mode of draining is not only unnecessary but 

 highly improper, upon principle — not that it 

 is impossible to drain land by carrying the 

 cuts down the hill, if there be enough of them, 

 for if a distance of ten feet be too great, it 

 might be reduced to five; but the principle 

 is wrong, for, as you very properly observe, 

 under-drains ought always to be conducted 

 on as gentle a descent as is expedient to 

 draw off the water, to prevent the possibility 

 of washing or cutting the bottom of the 

 drains, or they will blow up to a certainty. 

 Under-drains act mainly by capillary attrac- 

 tion, and will generally operate more effectu- 

 ally on a gentle slope than on a very rapid 

 one. I should say Smith's plan is contrary 

 to rhyme and reason. 



I have now before me a remarkably neat 

 little volume, "The young Farmers' Manual," 

 by J. Main, in which there are some very 

 interesting observations on this most import- 

 ant of all operations, and I should be glad to 

 copy them for the consideration of your read- 

 ers ; he goes on the common sense principle, 

 that all wet land requires draining, but it is 

 little short of insanity to drain a porous soil 

 tvhen no water rises from the subsoil, and 

 none can remain on the surface. He says, 



" The vk'hole art of draining consists in 

 obtaining a right knowledge of the causes 

 why one portion of the surtiice of the earth 

 is wet and retentive of moisture and another 

 not. The surface is composed of various 

 strata, some of which are pervious and others 

 impervious to water; it is variously elevated 

 or depressed, and as water always finds the 

 lowest place, if there be no obstruction to its 

 downward course, we find natural pools in 

 the hollows, and dry, porous earth on the 

 knolls ; but these circumstances are not al- 

 ways present, for we often see dry valleys 

 and spriniry hills, but this depends on the 

 character of the surface strata and subsoil, 

 for where there is much undulation of the 

 surface, many of the eminences are clay, and 

 any depressions on these heights are recep- 

 tacles for water ; to drain these pools, it is I 



only necessary to lay a course of draining 

 tiles into the nearest ditch. But many valu- 

 able fields are rendered worthless by the 

 abundance of land-springs ; these proceed 

 from porous strata lying between strata of a 

 more dense or clayey quality, and as these 

 often alternate with each other and crop out 

 at different heights on the sloping side of a 

 hill, they occasion much expense and labour 

 to drain it thoroughly ; but as the sources of 

 these springs are always above the place 

 where they ooze out, a drain to catch the wa- 

 ter must be made above the wet spot, and 

 opened down to the bed of clay over which 

 it percolates, when, if it be filled with stone 

 or coarse gravel, and led away off the bed of 

 clay, will for ever prevent the water appear- 

 ing again on the surface. But when several 

 of these land springs issue out one above an- 

 other, on the sloping side of a field, open 

 several diagonal drains across the slope, to 

 catch the downward currents, by which 

 means the water is checked in its course, 

 and effectually prevented from ever flowing 

 to the surface. But it sometimes happens 

 that the strata of clay and gravel lie so near 

 each other, that an iron bar or dibble driven 

 through the upper stratum of clay will let 

 off the water from the upper drain ; and it 

 was this perforation of the upper sustaining 

 bed of clay by dibbles" (that is now ridiculed 

 by Smith of Deanston) " that gained Elking- 

 ton so much honour and emolument in his sys- 

 tem of, and for his institutions for draining." 



In fixing the directions of drains, a regu- 

 lar descent must be obtained into the nearest 

 natural outlet, but very great care must be 

 taken that the fall from the source to the 

 outlet be not too precipitous, for otherwise 

 the drain, however well formed, will soon 

 become choked-up, in consequence of a rapid' 

 current always carrying sand and other loose 

 matter before it, until it accumulates against 

 some obstruction, when the drain blows up, 

 and is no longer of any use : a fall of one 

 foot in fifty is fully sufficient for any under- 

 drain. 



In a turnip field, on which I meant to fold 

 my sheep by means of hurdles, I noticed a 

 dip in one corner which was retentive of wa- 

 ter in wet seasons, and from which there was 

 no visible outlet; but I saw at the same time 

 that the nearest ditch was cut through a 

 bank of gravel, which appeared always dry ; 

 now it occurred to me although the gra- 

 velly bank was higher than the loamy dip, 

 that by digging a deep drain from the latter 

 — the wet dip — to the gravelly bank, a swal- 

 low might be gained, which would constantly 

 absorb all the v/ater which might at any time 

 be collected in the loamy soil ; I therefore 

 first sunk a cess-pool (according to Elking- 

 ton'a mode of draining) six feet deep, and 



