STRUCTURAL 151 



Diagram 58 shows a scheme for laying drains 

 over an area with a fall towards one corner. 



Ordinary land drains of porous clay 2 in. in 

 diameter are the best, but other patterns are 

 made, such as the horseshoe tile which is rested on 

 a flat sole. Instead of pipes rubble drains can be 

 formed consisting of stones laid at the bottom of a 

 ditch, on a uniform gradient. A good size in 

 section is 7 in. at the bottom, 9 in. at the top, and a 

 depth of 15 in. of broken stone. Finer stone, or a 

 sod, should be between this and the soil, but in 

 any case rubble drains are liable to become choked. 

 They can be laid with advantage in land where 

 young trees or shrubs are to be planted, for 

 while the plants are small drainage may be needed, 

 but as they grow and require more moisture, it is 

 for their good that the drains no longer act. 

 An even more primitive drain on the same principle 

 is made with bundles of brushwood. 



In the formation of a garden, drains are laid 

 after the surface has been brought to its determined 

 levels, and before the ultimate preparation of the 

 soil by manuring and trenching. Special draining 

 tools are used for laying pipes which enable very 

 narrow channels to be made without opening a 

 trench sufficient for a man to work in. These 

 and the special scoops form a smooth bottom on 

 which the pipes are laid. They are laid " dry/' 

 i.e. without cement at the joints, unless in the case 

 of the main drain passing near tree roots when the 



