30 TnE SOIL or the farm. 



of the district must be taken into account, as well as the 

 contonr of the surface, and the texture of the soil and 

 subsoil of the particular field. 



If the surface of the ground be leyel/ and the structure 

 of the soil uniform, the drains may be arranged at regular 

 intervals apart, with the feeders at right angles to the 

 mains, and the necessary slojoe must be gained by cutting 

 upwards from a sufficiently deep outfall. In any case the 

 mains must be placed at the lowest level, delivering into 

 a ditch or brook, and the minor drains should run into 

 them in the direction of the inclination of the ground. 

 When the inclination of the surface varies, though there 

 should be sufficient fall for discharge if the drains were 

 cut throughout to a uniform depth, yefc it is necessary to 

 observe a sufficient uniformity of fall in the pipes to 

 hinder any risk of a deposit of mud in any part of their 

 course. 



If the substrata consists of layers of various retentive 

 l")ower, their relative positions must be regarded in the 

 arrangement of the drains. Instead of following rigid 

 rules for fixing the proportionate depths and distances 

 of drains in light and heavy soils, we must determine 

 these points by reference to the thickness and order of 

 the substrata no less than by the character or texture of 

 the soil itself. 



Practically these are determined by digging holes four 

 feet deep here and there in a field and taking a drain of 

 the intended depth up the field in their neigliborhood. 

 The holes will fill with water if the land needs draining ; 

 and the effect of the drain in emptying them at distances 

 of three, five, seven yards, etc., will indicate twice that 

 measure as the proper interval to be adopted between the 

 drains. 



If the up]ier bed be retentive, and of such depth that 

 the drains cannot be cut completely throngh it, the best 

 system to ado2)t will be that of comparatively shallow 



