DRAINAGE. 



detected ; and one single drain or 

 ditch, judiciously disposed, may lay 

 a great extent of land dry if it cuts 

 ofT the springs before they run into 

 the soil Abundant springs which 

 flow continually generally proceed 

 from the outbreaking of some porous 

 stratum in which the waters were 

 confined, or through natural crevices 

 in rocks or impervious earth. A 

 knowledge of the geology of the coun- 

 try will greatly assist in tracing this, 

 and the springs may be cut off with 

 greater certainty. But it is not these 



main springs which give the greatest 

 trouble to an experienced drainer ; it 

 is the various land-springs, which are 

 sometimes branches of the former, 

 and often original and independent 

 springs arising from sudden varia- 

 tions in the nature of the soil and sub- 

 sod. The annexed diagram, repre- 

 senting a section of an uneven sur- 

 face of land, will explain the nature 

 of the strata which produce springs. 

 " Suppose A A a porous gravel 

 through which the water filtrates 

 readily ; B B a stratum of loam or 



ill- 



clay impervious to water. The wa- 

 ter which comes through A A will 

 run along the surface of B B towards 

 S S, where it will spring to the sur- 

 face and form a lake or bog between 

 S and S. Suppose another gravelly 

 or pervicus stratum under the last, 

 as C, C, C, bending as here represent- 

 ed, and filled with water running into 

 it from a higher level ; it is evident 

 that this stratum will be saturated 

 with water up to the dotted line E, F, 

 F, which is the level of the point in 

 the lower rock, or impervious stratum, 

 D, D, where the water can run over 

 it. If the stratum B B has any crev- 

 ices in it below the dotted line, the 

 water will rise through these to the 

 surface, and form springs rising from 

 the bottom of the lake or bog ; and 

 if B B were bored through and a pipe 

 inserted rising up to the dotted line, 

 as c, 0, the water would rise and stand 

 at o. If there were no springs at 

 S S, the space below the dotted line 

 might still be filled with water rising 

 from stratum C, C, C. But if the bo- 

 ring took place at G, the water would 

 not rise, but, on the contrary, if there 

 were any on the surface, it would be 

 carried down to the porous stratum 

 C, C, C, and run off. Thus in one sit- 

 uation boring will bring water, and 

 in another it will take it off. This 

 principle being well understood will 

 greatly facilitate all drainings of 

 234 



springs. Wherever water springs, 

 there must be a pervious and an im- 

 pervious stratum to cause it, and the 

 water either runs over the impervi- 

 ous surface or rises through the crev- 

 ices in it. When the line of the 

 springs is found, as at S S, the obvi- 

 ous remedy is to cut a channel with 

 a sufficient declivity to take off the 

 Avater in a direction across this line, 

 and sunk through the porous soil at 

 the surface into the lower impervious 

 earth. The place for this channel is 

 where the porous soil is the shallow- 

 est above the breaking out, so as to 

 require the least depth of drain, but 

 the solid stratum must be reached, 

 or the draining will be imperfect. 

 It is by attending to all these circum- 

 stances that Elkington acquired his 

 celebrity in draining, and that he has 

 been considered as the father of the 

 system. It is, however, of much 

 earlier invention, and is too obvious 

 not to have struck any one who seri- 

 ously considered the subject. In the 

 practical application of the principle, 

 great ingenuity and skill may be dis- 

 played, and the desired effect may be 

 produced more or less completely, 

 and at a greater or less expense. 

 The advice of a scientific and prac- 

 tical drainer is always well worth the 

 cost at which it may be obtained. 



" When there is a great variation in 

 the soil, and it is difficult to find any 



