Book IV. CARRYING DESIGNS INTO EXECUTION. 383 



are seldom well colored. The best in this respect in England, and also a good gravel 

 for binding, is the gravel of Kensington, to which good qualities it adds that of being the 

 most beautiful in the world. There are some very agreeable sea-gravels, formed chiefly 

 of small shells, or fragments of larger ones. The way to make a handsome walk with 

 this gravel is to mix it with about a tenth part of a composition consisting of equal parts 

 of brickdust and puzzolana earth or Roman cement. This done, and the gravel laid down 

 in a wet state, and well rolled, it will form a surface like that of shell-marble. 



1 958. Where a covering of sand is adopted, its thickness must depend on its qualities, 

 and whether sand is taken from preference or necessity. When sand is taken from pre- 

 ference, the intention is to produce soft walks, which shall yield to the feet like turf, in 

 which case its thickness may be from three to six inches ; but if sand is used because 

 gravel cannot be procured, then little more should be laid on than what is sufficient to fill 

 up the interstices of the upper surface of the substrata. Sometimes an attempt is made 

 to bind such sand, by mixing it with dried clay in a state of powder, or with the scrapings 

 of stone roads, and men watering and rolling ; but it is not often that this succeeds ; and 

 it may certainly be considered as unfortunate where the best walks about a residence are 

 covered with sand. 



1959. The covering of turf and earth (Jig. 373. b) should not be less than six inches in 

 thickness, that there may be sufficient pasturage and moisture for the roots of the grasses 

 in the dry season. For this purpose, the soil laid under the turf should be a medium be- 

 tween a stiff clayey and a loose sandy soil, so as more completely to serve as a sponge than 

 either. 



1960. Substitutes for gravel and sand are burned lumps of clay reduced to powder, 

 pounded bricks, stones, or slates, scoria, ashes, soaper's waste, coal, shells, sawdust, tan- 

 ner's bark, ferruginous earth, and even moss or peat-earth. Bark and peat-earth are 

 often used in Holland ; the former, when fresh, has much of the color of Kensington 

 gravel, and assorts well with vegetation. 



1961. Substitutes for turf are green mpsses recently gathered and stuck on mortar or 

 cement ; the same process with lichens from trees, or with flow-moss or heath-tops. 



1 962. The form of the surface of gravel, sand, and grass walks, should almost always 

 be flat ; or, in the case of gravel, gently raised in the middle, so as to throw the water 

 towards the sides, in approaching which it may sink gently into the substrata. But in 

 turf walks this should never be attempted ; as it is desirable, on account of equally 

 watering the plants, and retaining an equal firmness throughout their surface, that the 

 water should sink in where it falls. It is a common practice to form turf walks of solid 

 earth, without any regard to the substrata ; and this succeeds very well in dry soils, and 

 where such walks are little used, excepting in summer ; but whenever turf walks are to 

 be in constant use, the above is much the best way of forming them. Gravel and sand 

 have, in like manner, been laid on the surface of the soil in small gardens, and in very dry 

 sub-soils, and where this can be done with the attainment of the desired objects, it has this 

 advantage, that the roots of trees may range under the walks, as indeed always happens 

 in shrubberies and plantations. The scoria; of metals, coal-ashes, the refuse of mines and 

 glass-works, and other similar matters, are often used instead of gravel j but their color 

 seldom harmonises well with that of vegetation. 



1 963. The breadth of walks generally depends on the extent or scale of the whole residence, 

 and not of the particular garden or scene, which may be small, and yet connected with 

 greater. They should never be narrower than is sufficient to allow a party of two to walk 

 abreast, the minimum breadth for which is four feet six inches ; but they may be large 

 enough for a party of half a dozen, or in public walks, or walks in extensive pleasure- 

 grounds, avenues, &c, for one or two dozen. For the latter number thirty-six feet suf- 

 fices. Tlie direction of walks depends on their particular use, and connection with the 

 different scenes or subjects of gardening. 



1964. Alleys are smaller walks generally covered with a thin coat of sand, gravel, or 

 shells. In parterres they are sometimes of various widths, to suit the particular forms 

 which constitute the design ; and there also they are sometimes covered with different 

 sorts of gravels, shells, scoriae, &c, or paved with flints, pebbles, &c. ; but the alleys of 

 separation, in walled gardens, are generally two feet wide, and formed in right lines, 

 parallel to the main walks, or borders. Sometimes they are not gravelled, and at other 

 times they are covered with road-grit, or the scrapings of roads ; which, of course, is to be 

 considered as the powder of the material of which the road is made, mixed with vegetable 

 matter from the droppings of horses and cattle, and is considered as well adapted for 

 binding or forming a compact surface. 



1 965. Roads are walks on a large scale ; they are formed on the same general plan ; 

 but when of fifteen or twenty feet in breadth, and on a wet or retentive soil, they have 

 generally a drain on each side instead of one in the centre. On the sides of slopes, 

 where, during heavy rains, these roads intercept the water from the upper grounds, they 

 should have frequent gratings, or pierced stones, communicating with die drains on 



