THIRD ANNUAL YEAR BOOK — PART I. SS 



an ordinary tile drain. Any intelligent farmer with a home-made level 

 (Fig. 14) can do the work sufficiently well. If drains are not laid with 



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Fig. 14.— Grade level of light planed boards, made accurately as shown. To establish a 5 

 per cent grade, for example, bring the instrument to a level along the line of the drain 

 by use of spirit level F ; mark center ab; then raise the updrain end through a distance 

 one-twentieth of the length of the base line A C. The plumb line will cross the board 

 D E in some bine away from the center, a b. Mark this crossing as x y. The same 

 grade can then be found at any point in the drain by leveling till plumb line crosses at 

 a b, and then raising the updrain end till the plumb line crosses again at x y. A 

 uniform grade can thus be maintained. 



great care, low points are liable to form where the mud and sand will 

 collect and reduce the flow, and finally choke the drains altogether. 

 (Fig. 15.) After the drains have been carefully laid, the ditch should 



Fig. 15.— Poorly laid drain tile. 



then be half filled with rough, broken stones, or if no stones are avail- 

 able, with broken brickbats, coarse sand, gravel, cinders or some other 

 imperishable material. A little hay, sod or brush packed around the tile 

 to prevent silt from washing in and clogging the drains will be useful. 

 The ditch can then be tamped full of firm earth. Care should be exer- 

 cised in keeping the drains open and unobstructed at outlets. Under- 

 drains are useless unless outlets are provided; for if the outlet is ob- 

 structed, the water is kept standing in the drains until it soaks and 

 softens the foundation. 



CONSTRUCTION. 



PROPER CROSS SECTION. 

 The wearing surface of a road must be, in effect, a roof; that Is, the 

 section in the middle must be the highest part, and the traveled road- 

 way should be made, by consolidation, as impervious to water as pos- 



