FORMATION OF GARDENS. 119 



color, but this is easily changed by a thin layer of any other 

 material on its surface, which partly mixes and binds with it. 



Broken, or what is sometimes called rotten rock, containing 

 oxide of iron, is to be preferred to gravel for making a surface, 

 and pit gravel is to be preferred to river or sea gravel, as it con- 

 tains generally more oxide and earthy matter. Clay forms a 

 good under-surface, and when thinly covered with small gravel 

 and well rolled, forms a most excellent and durable walk. 

 Common gravel may also be mixed with coal ashes and lime 

 rubbish, which tends to bind it, and also with common garden 

 soil ; but this is a last resource. Gravel mixed with earth, and 

 more especially vegetable earths, has a great tendency to pro- 

 duce weeds, and is therefore very troublesome to keep clean. 

 It also readily absorbs moisture and becomes soft in wet weather, 

 and especially during winter frosts. 



Where expense is not spared, a composition may be made, 

 consisting of small shell gravel, or pounded granite, about one 

 tenth part of brick-dust, and cement, mixed together. This, laid 

 down upon a firm, prepared surface, in a wet state, and well 

 rolled, will form a surface as hard as marble. 



The form of the surface should be nearly flat ; grass walks 

 should be completely so ; gravel walks may rise slightly towards 

 the middle, but not so much as to affect the convenience of as 

 many persons walking abreast as the breadth of the walk will 

 admit. A walk six or eight feet wide should not fall more than 

 an inch towards each side, this being sufficient to throw the 

 water that falls on it towards each side, without being any 

 inconvenience to pedestrians occupying its whole breadth. 



If the walk be edged with turf, the crown of the walk should, 

 when finished, be on a level with the turf at each side, one inch 

 being quite enough for depth of edging ; besides, the walk gen- 

 erally subsides, while the verges become higher, for which an 

 allowance must be made. The same rule applies to walks 

 edged with box, which are most suitable in a kitchen garden. 



3. Borders and Interior Compartments. The width of the 

 borders and size of the compartments must be regulated by the 

 height of the wall or fence, and the extent of the garden. The 



