22 



THE GARDENER'S ASSISTANT. 



materials, and their greater weight as com- 

 pared with that of tiles. There are three kinds 

 of stone-drains: the box-drain, the couple-drain, 

 and the small-stone or rubble drain. 



The box-drain (fig. 810) is chiefly formed 

 with flat stones. Drains of this kind have to 

 be carefully built by the hand, and are pro- 

 portionately costly, but if well built and filled 

 up with a foot of small stones or rubble on the 

 top of the covers, they act effectively, and will 

 last for ages. For permanent work they are 

 worth their cost. They are made by selecting 

 the largest and flattest stones for soles and 

 covers. Great care must be taken to lay the 

 upper face of the soles perfectly even, so that 

 no part of a bottom stone rises half an inch 

 above the general run, which can be ascer- 

 tained by placing a straight-edge along their 

 face. The bottom being thus made flat and 

 fairly smooth to prevent obstruction and facili- 

 tate the flow of water, the sides are built to 

 the required height, packing the smaller stones 

 neatly in between the larger ones to keep them 

 firm and steady in their position. The covers are 

 then laid on. taking care to place their flattest 



Fig. 81ti. Fig. 811. 



sides downwards, so that there may be no pro- 

 jections into the cavity. Small stones are then 

 put over the covers to a depth of from 9 

 inches to a foot, and a layer of turf or other 

 tough substance should be placed over the 

 stones in order to prevent the soil from mixing 

 with them. If 3 inches in depth of coal-ashes 

 can be laid over the stones they will prevent 

 worms working down and interfering with the 

 drainage. 



The couple-drain (fig. 811) is formed by put- 

 ting flat stones on the bottom for a sole, and 

 upon this two other stones are placed, with their 

 upper edges leaning against each other, so as to 

 form a triangular cavity. The spaces between 

 the sides of the drain and those of the cut trench 

 may be filled up with smaller stones, and precau- 



tions similar to those employed in the preceding 

 case are necessary to prevent the soil from clos- 

 ing up the drainage. 



Figs. 812 and 813 represent sections of small- 

 stone or rubble drains. They are 7 inches wide 



Fig. 815 



Fig. 813. 



at bottom, and 9 inches wide at the top of the 

 stones, the depth of the latter being 15 inches. 

 These are the ordinary proportions, and make 

 a good drain. The stones should pass through 

 a 3-inch ring; and rounded land- or water-worn 

 stones are better than broken rock or stones 

 with flat sides and sharp angles. It is a good 

 plan to put a layer of very small stones, several 

 inches thick, over the others, as represented in 

 fig. 813; for by so doing, the earth is prevented 

 from passing down so readily among the lower 

 portions of the drainage. Rubble drains are 

 not so well adapted for gardens as box-drains; 

 for rich soil, such as that of gardens, usually 

 abounds in earth-worms, by the workings of 

 which the drains are apt to be compactly 

 cemented. They may, however, be adopted 

 with advantage in some cases; for example, 

 an orchard may require a certain amount of 

 drainage when the trees are first planted; but 

 when they get large, it is frequently the case 

 that they require all the moisture they can get; 

 so that if the rubble drains cease to act after 

 the lapse of some years, the want of drainage 

 will not be felt. 



Tile-drains. — There are several kinds of these. 

 Fig. 814 represents the common horse-shoe tile 



Fig. 814. 



and its sole. The latter is sometimes dispensed 

 with, but this is bad economy, because in most 

 subsoils the bottom of the drain becomes soft, 

 and allows the horse-shoe tiles to sink, dimin- 

 ishing the opening not only by the amount of 



