LECTURES AND ESSAYS READ AT INSTITUTES. 



271 



and lakes, or miderdrains, in fact, as an artificial water course of too great a 

 size to be carried under grouud with the means at present at our command. 

 Its use is never to be commended when an underground drain can be substi- 

 tuted. It is open to the objections of being but a temporary construction, 

 dangerous and inconvenient to cross, usurping valuable land, inefficient in its 

 action, as the water reaches it rather by washing in at the surface than by per- 

 colation. 



The open ditch has its part to play in the drainage works of a country, and 

 in many places can never be replaced by the underdrain. It is, however, 

 at best, a temporary construction, unless a heavy body of water flows through 

 it; for every rain carries particles from its banks to its bottom, and every 

 winter's frost ezerts its power to fill it up, so that the construction of an open 

 drain implies a continual bill for annual repairs, or else a gradual lessening of 

 its efficiency. 



THE UNDER-DRAIN. 



Under-drains are the only ones that can in any way be considered as perma- 

 nent, and these are not permanent unless properly constructed. 



The outlet must be the first consideration in locating under-drains. It 

 must be sufficiently low to allow a free flow of water from the drains. It is 

 often a difficult thing to secure a good outlet, especially in a low, flat country, 

 but it must be done before any successful drainage system can be carried out. 

 The construction of township and county ditches has often to be resorted to 

 before good outlets for tile drains can be secured. 



DEAINAGE BY WELLS. 



In several instances outlets have been obtained by digging large wells until 

 water-taking strata are found, as shown in Fig. 3. As the construction of 

 these wells forms an important method in drainage, and as I have much faith 

 in their efficiency in many localities, I take time to describe in detail the 

 method of constructing them. 



Since, in order to be successful, water- 

 taking strata must be found, this system 

 is somewhat uncertain in its operation. 

 There is no doubt that, in certain locali- 

 ties, water-taking strata are not to be 

 found, or lie so deep as to render the sink- 

 ing of wells to them impracticable. This 

 uncertainty has, of late years, rendered 

 this method of obtaining an outlet so 

 unpopular that in practice it has seemed 

 likely to be lost sight of. It has, liow- 

 evei', been tried with success in Michigan, 

 Drain-wen. Fig. 3. at Marshall, near Lake Superior, and in 



several other places on a small scale, and I have not heard of any trials in this 

 State being unsuccessful. 



This system is so inexpensive when it will work, that I would advocate its 

 trial in the drainage of all large swamps where an open outlet cannot readily 

 be obtained. The water-taking strata are usually of coarse sand or gravel, or 

 sand and gravel combined. By driving a capped two-inch gas-pipe down a few 

 feet at a time and withdrawing it, the character of the successive strata of earth 

 can be accurately determined with little expense. The water-taking character. 



