OF EARTH. 



43 



Hungry grounds require to have tjie cause well looked into, (the water 

 turned as above directed,) or if in want, such as is well enriched. 



Lands that are hot and burning, allay with swines' dung (as some say) 

 the coldest ; or with neats', which wiU certainly refresh it. 



but the width at the bottom must Tf)e regulated by the nature and size of the materials 

 intended to be used. If the drain is to be made of bricks ten inches long, three inches 

 thick, and four inches ill breadth, then the bottom of the drain must be twelve inches; 

 but if the common sale bricks are used; then the bottom must be proportionably contracted. 

 In both cases there must be an interstice of one inch between the bottom brick and the 

 sides of the trench, and the Vacuity must be filled up with straw, rushes, or loose mould. 

 For the purpose of making these drains, I order my bricks to be moulded ten inches long, 

 four broad, and three thick. These dimensions make the best drain ; and I beg leave to 

 be understood, throughout this essay, as speaking of bricks formed in the above manner. 



" The method I pursue in constructing my main drains is as follows : 



" When the ground is soft and spongy, the bottom of the drain is laid with bricks placed 

 across. On these, on each side, two bricks are laid flat, one upon the other, forming a 

 drain six inches high and four broad. This is covered with bricks laid flat. Fig. 2, plaie 1. 



" When I first engaged in this mode of draining, I conceived that in places where the 

 bottoms of the main drains were firm and solid, as of clay or marl, it would be an unne- 

 cessary expense to pave them with brick. Under this idea, I recommended them to be 

 constructed as in plate 1, Jig. 3, the sides being formed by placing one brick edgeways, 

 instead of two laid flat. But after the experience of some years, I found that the access 

 of air, and the alternation of wet and dry, occasioned the hardest clay or marl to crumble 

 down, whereby the side bricks, not having a paved bottom, were made to fall in. From 

 the experience of this circumstance, I now direct the main drains to be invariably paved 

 with brick, as repeated in /)/a/e 1, ^g. 2. This will render them as lasting as the sod, or 

 pipe-drains, which I have found free and open after being constructed twenty-five years. 



" When stones are used instead of bricks, the bottom of the drain should be about eight 

 inches in width. And here it will be proper to remark that, in all cases, the bottom of the 

 main drains must be sunk four inches below the level of the narrow ones, even at the point 

 where the latter fall into them. 



" The main drains should be kept open till the narrow ones are begun from them, after 

 which they may be finished : but before the earth is returned upon the stones or bricks, it 

 will be advisable to throw in straw, rushes, or brush-wood, to increase the freedom of the 

 drain. 



" The small narrow drains should be cut at the distance of sixteen or eighteen feet from 

 each other, and should fall into the main drain at very acute angles, to prevent any stop- 

 page. At the point where they fall into, and eight or ten inches above it, they should be 

 made firm with brick or stone. 



" In making the narrow drains I employ four labourers. The first man, with a common 



3 L 2 



