On Draining. 



511 



thereby ; but from certain indications, after a time, that a -perfect 

 effect was not obtained, other drains from 5 to 6 feet deep and 

 120 yards apart were put in, and the result is that not a single 

 one of the shallower drains has run since, and the land is now 

 perfectly dry at all times. But is this any proof that the same 

 result will follow a similar plan of operation on the uniformly 

 tenacious subsoils? Most certainly not. Suppose 4-feet and 

 3-feet drains to be laid alternately throughout a clay-land field 

 of uniform contour and tenacity, it is quite possible, and even 

 probable, that the 4-feet will run first after rain. But take 

 two distinct portions of such land, having similar characteristics 

 in all respects, and drain the one at from 30 inches to 3 feet deep, 

 and from 18 to 24 feet apart, as may be judged necessary to 

 insure that completeness for which we contend, and the other with 

 drains from 4 to 4£ feet deep, and 26 to 40 feet apart, as may be 

 deemed sufficient, and I maintain it is a physical impossibility for 

 these deeper drains to run before the shallower, or to dry the 

 land in the same time, or so effectually; — that they will run 

 the longest is manifest, and is of itself an evidence of their in- 

 sufficiency. 



The more clearly to demonstrate this, let us look at a section 

 of such drains, drawn to the same scale : — ■ 



1 



1 — Shows 4-feet and 3-feet drains, cut alternately at 21 feet 

 apart, under which circumstances we say, it may be probable 

 that the deeper ones will run first after rain. Each 3-feet 

 drain has on either side of it an opening for the exit of the 

 water at a foot lower level, the effect of which, as you will rea- 

 dily imagine, may be that when the rain has percolated to the 

 bottom of the 3-feet drain, instead of passing off, its natural 

 tendency is to descend to the lower level, where it meets with 

 a fully saturated bed, and having no longer a lower attraction, 

 of course runs off by the drain at that level This may not 



