1G2 THK YTT.LA GARDENEll. 



is ascertained from experience, rats will not do, unless where the water is 

 clear, and hoth sides of the trap are fully exposed to the day, in which case 

 they will dive under the dip-stone and ascend on the other side, though the 

 stone should descend several feet into the pit. It should be observed, that 

 only a small space of about half an inch is left between the dip-stone and the 

 cover ; this space is essential, in order to admit the passage of air ; for 

 though the water woidd escape witliout it, yet it would be at a much lower 

 rate. It may be useful to observe here, that all underground drains from 

 offices, or from any part of an estate, which are intended to carry away night 

 soil, or any earthy matter, ought to have a certain slope or inclination ; with 

 the bottom of the drain not flat, but concave, and generally so much so as 

 to form the section of a semicircle. A semicircular bottom, and a slope of 

 1-^in. in 10 ft., it has been ascertained by builders, will enable any drain, 

 with a tolerable supply of water, to carry off all the nightsoil suspended in it; 

 but, where there are sand or small gravel, pieces of bones, broken crockery, 

 and other matters of that description, to be carried away, the slope requires 

 to be at least 3 in. in 10 ft. 



251. If the subsoil of the property he dry, very few drains in the grounds, 

 for the purpose of drying the soil, will be required ; but, if the soil be loamy, 

 or on a retentive bottom, every part of it will require under-draining. The 

 kitchen- garden must be more thoroughly drained than the general surface, 

 which is to be laid down under grass, or planted with trees, because the 

 excellence of culinary produce depends chiefly on the culture of the soil; and 

 an extra attention to drainage must be paid in the flower-garden, and in all 

 those parts of the lawn (especially such as are near the gravel-walks) v/hich 

 are liable to be much walked on in autumn or spring. Whether the subsoil 

 be naturally dry or wet, every walk and road, whether in the kitchen-garden, 

 the flower-garden, the pleasure-ground, or forming the approach roads to the 

 mansion, and the branches to the oflfices, will require to be drained, for the 

 sake of absorbing as completely as possible the v/ater that falls on them during 

 heavy rains, or is produced by the thawing of snow. For this purpose, a 

 drain should be conducted along one side of the walk, under the gravel in the 

 kitchen-garden, and either vmder the gravel, or under the turf, in the pleasure- 

 grounds; and to this drain small grated openings should be made, at regular 

 distances, along one side of the walk. Where the walks in the pleasure- 

 ground are of great length, branch drains require to be introduced at certain 

 distances in the lowest situations, in order to conduct the water collected in 

 the drains along the walks to the nearest public drain. The drains along the 

 walks should be what are called box or barrel drains ; the former having a 

 buttom and square sides, with a flagstone cover, 

 as in fg. 76. ; and the latter being a circular 

 cylinder of brickwork, a section of which is 

 shown in fg. 77. Small iron or stone gratings 

 on the surface communicate with the drains 

 by short upright shafts, 9 in. square in the 

 clear within; and, in the bottom of the drain, 

 immediately under each shaft, a pit is formed, and walled on the sides, 

 a foot square within, and from 1 ft. to 2 ft. or more in depth, as in the 

 section fg. 78. The use of this pit is to receive the sand that is carried 

 through the grating with the water, immediately after very heavy showers in 



