WALKS. 



304 



WALKS. 



is not only necessary to have a drain 

 under the walk throughout its whole 

 length, hut a branch drain to some 

 natural outlet is essential at every 

 change of surface. These drains are 

 not only intended to carry off the 

 underground water, hut also that 

 which collects on the surface, and 

 finds its way to the sides; and for 

 this purpose there are small cross 

 drains formed at certain distances, 

 which communicate from the sides to 

 the centre, and these side drains com- 

 municate with the surface by a small 

 upright tube or well, covered by an 

 iron grating or by a flag-stone pierced 

 with holes to admit the water. Some- 

 times the main drain, instead of being 

 formed under the centre of the walk, 

 is made at one side, and sometimes in 

 the case of walks through a lawn the 

 drain is made under the turf ; but in 

 this case, as in the other, the small 

 cross-drains communicate with it, 

 and are furnished with gratings on a 

 level with the surface of the sides of 

 the walk. In general, these gratings 

 are placed close to the edge of the 

 walk, more especially when it passes 

 through dug ground edged with box, 

 or where there is little ground to 

 spare ; but when it passes through a 

 lawn, the gratings are best placed in 

 small recesses in the turf at the sides. 

 In the case of dry soils with a porous 

 subsoil of gravel, sand, or rock, drains 

 may be dispensed with altogether ; 

 and in those parts of the country 

 where the kind of gravel used does 

 not hind so as to form a sufficiently 

 smooth and compact surface to prevent 

 the water from sinking into it, the 

 side gratings may be dispensed with. 

 In walks on very uneven surfaces, such 

 as where they are conducted up and 

 down declivities, considerable care in 

 the construction is required, in order 

 to prevent the gravel from being 

 washed away during heavy rains, or 

 the thawing of snow. Two things are 



requisite for this purpose; very com- 

 plete drainage, with gratings on both 

 sides, not more than two or three 

 yards apart ; and having the surface 

 of the walk raised much higher in the 

 middle than usual, so as to throw the 

 water immediately to the sides, and 

 never to admit of a current in the 

 direction of the walk. The next re- 

 quisite is a much coarser gravel than 

 usual, in consequence of which the 

 water of rain or snow cannot wash 

 away the sandy particles. The most 

 effective mode, however, is to wash 

 the gravel quite clean, so as to leave 

 no particle smaller than a large goose- 

 berry, or larger than a small apple, and 

 to mix the whole with Roman cement. 

 Were it not for the disagreeable dark 

 colour of asphalte, walks on steep de- 

 clivities laid with this material would 

 be preferable to any others, as being 

 by far the most durable. 



In the operation of forming walks, 

 the first step, after the line has been 

 marked out, is to take the levels of 

 the surface, so as to determine the 

 degree of inclination necessary for 

 carrying off the water, and also what 

 quantity of soil will have to be re- 

 moved on each side of the walk, so as 

 to reduce the whole to a uniform 

 surface. The next step is to mark 

 out the width of the walk, after which 

 the soil is to be excavated. The 

 depth of the excavation will depend 

 on the nature of the subsoil. If that is 

 dry and absorbent, such as gravel or 

 rock, then the depth need not be 

 more than a foot or eighteen inches ; 

 but if the subsoil is retentive, such as 

 clay or loam, then the depth, at least 

 in the centre of the walk, should be 

 between eighteen inches and two feet, 

 and it should be at least one foot in 

 depth at the sides. The drain may 

 be made in the centre, that being the 

 deepest part ; and this being done, the 

 excavation is to be filled up to within 

 nine inches of the surface with small 



