Practical Directions 259 



apt to become filled up or obstructed by the roots of plants 

 entering them, or by the action of moles, rats, rabbits, etc. 

 Drains formed with rubblestone or any similar material are 

 therefore superior to tile drains in gardens. Where rock is 

 plentiful it can be broken into pieces of two to three inches 

 diameter and placed loosely in the common drains, to the 

 depth of twelve or fifteen inches; or similar pieces of broken 

 brick, flint, coarse gravel, large cinders or clinkers, or what- 

 ever else of a like nature abounds in the district can be used 

 instead of rock. A rubble drain should not be less than five 

 or six inches wide at the bottom. 



For main drains, however, tiles of 4-6 inches in diameter 

 will be better as the principal conduits of water, but these 

 should also be covered with at least twelve inches of the 

 material of which the other drains are composed. Glazed, 

 or "Akron" tiles, where they can be procured, will always be 

 preferable to porous tiles; especially those which are made 

 with collars to cover the joints have a decided advantage 

 over those ordinarily used. 



Over the rubble with which both classes of drains are thus 

 filled up, a sod of from one to two inches in thickness and the 

 full width of the drain should be inverted, to prevent the soil 

 from crumbling and washing down among the stones and 

 clogging up the interstices. As this sod will last many years, 

 until the soil has become quite consolidated, it will be a most 

 useful auxiliary to the drains, and tend to keep their action 

 more perfect. Fig. 72 represents a minor rubble drain, with 

 the broken stone in it (b) and a sod (a) inverted over the 

 latter. Fig. 73 shows a main drain which is deeper and 

 wider, having a tile (c) at the bottom and being half filled 

 with rubble (b) with a sod (a) over the broken stone. The 

 scale is four feet to an inch. 



All drains should be cut out smoothly with even sides and 



