160 MASSACHUSETTS AGRICULTURE. 



Concerning the depth of drains and their distance from each 

 other, there are various views and opinions entertained by 

 experienced drainers. These may be accounted for in part by 

 the difference in soils. It is no more strange that this should 

 be so, than that husbandmen should differ in reference to the 

 depth of ploughing. Farmers are not generally informed as to 

 the depth which the roots of cereals and other crops penetrate. 

 It is said the smaller grains send down roots to the depth 

 of three or more feet ; and mangold wurzel four or five feet. 

 All good arable lands should then be drained to the depth 

 of three feet. To do this, the drains must be sunk four feet 

 deep from the surface. The interstitial canals existing in the 

 soil have been compared to tubes, the downward pressure being 

 increased by the greater length of these. If the drains are 

 shallow, the tubes short, the pressure will be less, thus drain- 

 ing more slowly. The truth of this doctrine is demonstrated 

 by practical observation ; for deep drains run sooner and faster 

 after a rain than shallow ones. Hence the reason why deep 

 clay soils require deep draining in order to render it effectual 

 and beneficial. The theory of inexperienced reasoners on this 

 subject is in opposition to facts. The theoretic objection to the 

 deep drainage of clay soils is as good, theoretically, against 

 shallow as deep drainage, which is, that the water will not 

 percolate to the drain. 



Before drains can become effective, either in deep or shallow 

 draining, the pores and interstices of the soil must be emptied 

 of the stagnant waters that have filled them. This requires 

 some time. Where there are slopes or ridges on the surface to 

 be drained, the drains should be run across these at an angle 

 of forty-five degrees. 



Drains that were sunk to the depth of four feet, after ten 

 years, have been found six or seven inches nearer the surface 

 than when the pipes were laid. Hence no thorough drainer 

 should be content short of four feet in depth, unless there are 

 physical objections to this in the soil or fall. 



Many fail in constructing their drains too far apart. Mr. 

 Parks, already referred to, did so. In very tenacious clay soils 

 drains that are four feet deep should be from eighteen to twen- 

 ty-five feet apart ; if three and a half feet deep, from eighteen 

 to twenty-one apart. On soils more porous, twenty-five to 



