DRAINAGE OF SOILS. 
322 
Water-Co arses, Protecting River Banks, Embanking Lands, Drain¬ 
ing in Sweden, Illustrated with nine" copper-plate engravings, besides 
several wood-cuts, illustrative of the plan of forming water meadows 
and draining, on Mr. Stephen’s principle. 
DRAINAGE OF SOILS, COMPOSED OF ALTERNATE BEDS OF 
CLAY AND SAND-RIDGES. 
Soils composed of an intermixed variety, and when clay predom¬ 
inates, are attended with much greater difficulty in draining than 
those in which both the surface and internal strata are more regularly 
disposed. In such soils, where every reservoir of water is uncon¬ 
nected with one another, being separated by means of clay beds or 
dykes, the partial collections of water which they contain are so much 
augmented in rainy seasons, as to be filled to the level of the surface 
of the surrounding clay, which it overflows, and renders it so wet and 
sour, that all kinds of crops are stinted in their growth. As these 
sand ridges have no communication with each other, a separate drain 
is required from each in order to reduce the water in them. The 
outlet drain must be made from the lowest part of the field to the 
sand ridge situated at the highest and most distant part, and to be 
carried in such a direction as to touch, if possible, some of the inter¬ 
mediate sand ridges, (as shewn in plan 7,) whereby a considerable 
extent of drain will be saved. From the outlet drain, branches must 
be carried to each of the sand ridges, which, when made sufficiently 
deep, will draw the water from them, and prevent it wetting the ad¬ 
jacent surface. Although the water oozes out all the way round the 
sand ridges, a sufficiently deep drain on the lower side will, in many 
cases, extract the water from both sides; but when the ridges are of 
considerable extent, and the sand of a very fine quality, so as not to 
allow the water to pass through it freely, the drain must be continued 
all the way round. 
In many cases, the whole of the wetness proceeds from the water 
in the upper sand ridge passing over the intermediate spaces of clay, 
and through the different ridges below. When this happens, the 
drainage of the whole field may be accomplished with much less dif¬ 
ficulty than in the former instance. After the outlet drain has been 
made the upper drain must be cut, which will intercept the water, 
and may, by this means, render the lower drains unnecessary. It is 
evident from this, that the water breaking out of the sand ridge in 
the highest part of a field, may be the sole cause of injury to a con¬ 
siderable extent below; it is, therefore, expedient, in draining land 
of this description, that the water in the upper side of the field should 
be first cut off, and its effect ascertained before any more drains are 
made in the lower part. 
