UNDERDRAINING. 119 



drainage. I know many acres in this county, composed of a 

 thin layer of loam and humus, upon a shallow bed of clay, 

 beneath which is found a deep stratum of gravel. The clay is 

 so tenacious that a great portion of the surface water never 

 penetrates it into the gravel filter beneath, but lies stagnant on 

 the level places, and flows down the slopes until the valleys are 

 constantly inundated. They yield but little. They need only 

 thorough drainage to become warm and fertile. Swamp lands 

 require a different mode of drainage ; and although some may 

 differ from me, I doubt if thorough drainage is applicable to 

 such lands. A swamp is usually composed of a collection of 

 decayed vegetable matter, of greater or less depth, occupying 

 what may once have been the bed of a lake or pond. Through 

 it or from it usually flows a stream, and the land itself may 

 almost be said to be afloat. The subsoil is very often below the 

 reach of any ditching. The level of the water may be governed 

 by the outlet. In its natural condition, the water is usually 

 almost as high as the level of the land. This level of the water 

 may be reduced in proportion to the fall which can be provided 

 at the outlet by digging — seldom more than two or three feet 

 below the surface of the soil. If, therefore, by a proper arrange- 

 ment of open ditches and a sufficient outlet, the water is caught 

 as it flows from the hill sides, and is conducted out of the 

 swamp, you will have just as many feet in depth of a porous, 

 peaty soil, as you have reduced the level of the water — no more 

 — perhaps, and probably less, on account of the settling of the 

 swamp, as the water is drawn off. This soil, composing islands, 

 so to speak, between the open ditches in which water stands, 

 never loses its porosity ; and it usually requires some applica- 

 tion of gravel or clay upon its surface to bring it into a condi- 

 tion fit for cultivation. It has no surface water, and it has no 

 subsoil that has been reached. It is in reality agriculture 

 afloat, and it must remain afloat so long as the reservoir of 

 water beneath it is supplied, and not emptied. I speak of 

 swamps as we usually [find them in our own county, and in 

 many parts of Massachusetts. I do not think tiles or blind 

 drains of any form are applicable to such tracts of land, for I 

 consider a firm subsoil as almost indispensable to the proper 

 use of tiles, not only on account of the solid basis upon which 

 they ought to lie, but on account of their capacity for discharg- 



