149 



success. He published his system to the world, and continued to im- 

 prove it for many years. 



The principles of Smith's system seem to have been known before 

 his day, but it remained for him to bring them together, and form them 

 into a regular plan, the chief peculiarity of which consists in the diret- 

 tion of the drains, namely, up and down the dechvity. 



The main drains always run through the lowest parts of the field, 

 and are always covered; ditches, or open drains are found to be much 

 more liable to obstruction than those which are covered. If the field 

 is large, it will be necessary to have sub-drains judiciously placed, so as 

 to receive the water of the small drains, and convey it to the main drain 

 or to the outlet. 



Smith made his drains 30 inches deep, 12 inches wide at top, and 4 

 inches at bottom ; the sides being sloped wedgelike. The main drains 

 must always be at least six inches deeper than the parallel drains. 



Smith placed his drains at intervals of 15 feet; but it should be borne 

 in mind that his soil was extremely wet 



The soil in Michigan is generally wet by surface water, or that which 

 arises from rain and snow, and when this is absorbed or removed, the 

 soil sometimes becomes too dry. It is evident that in Michigan, drains 

 are principally required for the purpose of removing surface water, and 

 they may be placed at much greater distances, than if the land were 

 wet by springs. In many cases they may be placed at intervals of 4 

 rods, or 66 feet asunder. 



I am an advocate for deep drainage where such is practicable, but in 

 level districts it will sometimes be very difficult to find a fall, or outlet 

 for drains which exceeds the depth of three feet 



In former times, wide, open drains, were made use of, but modern 

 skill has discovered that narrow, covered ones, are much better; as the 

 water, when confined in the bottom of a narrow drain, rises, and runs 

 with a stronger current, than if it wore permitted to spread on the bot- 

 tom of a wide drain. It is thus enabled to clear away sand and other 

 obstructions and to make a passage for itself. 



In Michigan the land is generally too dry in summer, and too wet in 

 the spring and fall ; thorough draining will bring it to an evener tempe- 

 rature or condition. The removal of stagnant water will have the effect 

 of increasing the fertility of the soil, and the salubrity of the climate. 



