240 



CASSELL'S POPULAR GAEDENTN-G. 



question of size brings us to another point of much 

 moment. 



The Materials used for Drains. — There is 



a general consensus of oxjinion that tiles are the best 

 materials. Among their other merits some also think 

 them warmer than stones. Either, of course, quickly 

 become assimilated to the temperature of the soil, 

 but as stones conduct heat faster than tiles, they 

 feel colder, and hence the origin of the fancy that 

 stone drains are cold. Doubtless, next to tiles there 

 is nothing like good sound stones for drainage. 

 They should, however, be fresh and good, and of as 



So strong does this domed soil over the crown of 

 drains, especially if of a semi-tenacious character, 

 become, that it is no uncommon thing to meet with 

 drains that have been excavated for fifteen or twenty 

 years, and merely filled in with a little brushwood or 

 straw, stni retaining their form, and discharging their 

 drainage functions, years and years after the perish- 

 able materials had disappetired and been washed 

 away. 



Fagot, Furze, Brush, and Straw Drain- 

 ing. — These are, or rather have been, practised 

 very extensively where stones are scarce, and where 



nearly as may be uniform 

 hardness and quality. The 

 land pickings, and general 

 collections of builders' 

 rubbish and effete brick- 

 bats, &c., sometimes used 

 for drains, are very inferior 

 to chalk, flint, river or sea 

 shingle of sufficient size, 

 or the refuse or inferior 

 stones of the quarries. 



These may be used of considerable size, especially 

 towards the bottom of what are called rubble drains. 

 The rough stones keep the water-course open, main- 

 taining a free course for the water as in the case of 

 box, angle, or tile drains ; while the smaller stones 

 at succeeding elevations, and the yet smaller on the 

 surface of the drain, act as percolators, and also as 

 barriers to the passage of silt into the drains. 



To make security doubly sure against these 

 blocking tendencies of the soil, a thick turf is often 

 inserted over the upper layers of fine stones, or a 

 thin covering of straw is placed over these or the 

 tiles. Buried thus, the straw will last long enough 

 to keep the soil out of the drains until it (the soil) 

 has once more become so consolidated as to form an 

 indestructible arch over the drainage material, which, 

 though not impervious to water, is to the passage 

 through of any sand or silt. 



Fig. 19.— Bubble Drain 



no other hard material 

 abounds. They are fairly 

 effective and durable, but 

 are altogether out of char- 

 acter and form for garden 

 purposes. 



Turf Drains. — The 



same may be said of these , 

 but they answer well in 

 old meadows, where the 

 turf is thick, fibrous, and strong. It used to be cut 

 almost two inches thick and securely placed on the 

 artificial ledge cut out for it near the base of the 

 drain, the base section being miade as narrow as 

 possible, as ia No. 1, Eig. 18. It is said on good 

 authority that some of these drains have lasted sound 

 and good for periods so prolonged as from twenty 

 to thirty or even fifty years. By this it must not, 

 however, be understood that the tm-f lasts so long 

 as that— only that the earth has formed a solid arch 

 over it, and the drain keeps rimning. 



But none of these perishable materials should find 

 any place in garden drains, as in these only the 

 best and most desirable ought to be used. 



Outlets. — It is hardly too much to say that the 

 weakest parts of drains are in their outlets. Great 

 care and trouble are often expended ia the planning 



