38 THE ART AND PRACTICE OF LANDSCAPE GARDENING. 



be taken on numbered pegs, at a minimum distance of 100 ft. 

 apart, and the gradient line must be marked on the plotted section ; 

 that will give the depth of cutting or filling, at the position of each 

 peg. It is profitable if you can so arrange the gradient that 

 the soil from a cutting is sufficient for all filling required without 

 length of lead ; yet careful regard must be given to treating the 

 gradient, so that earth may be obtained at any particular point for 

 raising mounds for planting, or for other purposes. Some difference 

 in the slopes and gradients for the approach drive, and for the 

 back drive, should be made ; the former should be flatter and more 

 finished than the latter. When the levels have been settled the 

 drain can be put in ; the capacity of the drain must depend on its 

 length, and on the quantity of water it will have to carry off. If 

 only surface water from the road is to be conducted, 3 in. pipes 

 are sufficiently capacious for a distance of 200 yds. ; but for a longer 

 distance 4 in. pipes are needed. In estimating the quantity of water 

 that is to be provided for, regard must be given to the surface 

 drainage which may come on to the road from falling ground above, 

 unless the general drainage be quite independent. 



The drain is best placed in the centre of a road, with gully 

 holes wherever necessary for the gradient. Drains may, however, 

 be placed at the sides, and they should be filled up with porous 

 material. Gully holes on drives should be built in mortar ; though 

 in garden walks they may be built "dry" that is, without mortar. 

 In long drives through parks, drains are frequently dispensed with, 

 and the water turned on to the grass land at convenient intervals. 

 On drives, 9 in. gratings and frames are generally sufficient ; for 

 garden paths, 7 in. gratings are large enough. On perfectly level 

 roads, or on steep gradients, say from i in 10 to i in 15, gully holes 

 should be 25 yards apart ; but on a slight incline they may be as far 

 apart as 50 yards. On walks they should be more frequent, because 



