168 On the Drainage of Land. 



each sod lapping over the end of its neighbour (see fig. 4), and the drain 

 is filled up with earth. The sod, if carefully cut, fits closely into the 

 drain. It will bear a great weight: indeed the greater the weight upon 

 it the more closely it is wedged down against the sloping sides of the 

 drain. In this respect our drains seem to be superior to those made 

 with ledges or shoulders to support the sod ; for in such drains the 

 weight rests chiefly upon two points, whereas in our wedge-shaped drains 

 the whole of each side shares in the pressure. 



Where the soil is tender, the drain is made a little larger, and a larger 

 sod is filled in ; or a few thorns are placed in the drain to support the 

 tender earth. In sand or gravel-beds, or other very bad places, it is well 

 to lay tiles as far as the soft soil extends. In very wet furrows it is 

 well to cut the drain a little on one side of the furrow, for both the soil 

 and the sod are generally sounder there. 



Drains of this kind, if carefully made, last many years. In the only 

 case in which I have known well-made sod-drains require to be renewed, 

 they had lasted about twenty years. In cutting ditches, sewers, &c., I 

 have lately fallen in with sod-drains considerably more than twenty years 

 old, which were as sound as when they were first made. The usual price 

 per acre (of 24 running yards) for making sod-drains is 10c/., and \s. per 

 running acre for the main-drains. Where the soil is stony I have 

 given as much as 1,?. per acre for the sod -drains, and 1^. 6d. for the 

 main-drains. In counties where labour is cheap the expense would pro- 

 bably be less. 



The expense of draining an acre of land with sods may be estimated 

 as follows : — 



20 running acres of sod-drain, at 10c?. per acre 

 Tiles for main drain, say ..... 

 Laying do. at 1.^. per 24 yards, say 



Total expense of sod-draining an acre of land . 18 6 



No stubble or other material is required to lay upon the drains. Ac- 

 cording to this estimate the expense of draining with sods is less than a 

 third of the expense of draining with tiles. Supposing sod-drains to last 

 twenty years, the interest of the money saved by substituting sod-drains 

 for tile-drains will more than pay the expense of renewing the sod-drains 

 ad wfiniium. 



I have drained between sixty and seventy acres with sod-drains, and 

 so well am I satisfied with them, that I intend to drain about as much 

 more in the same way. 



I am, Sir, 

 Your obedient servant, 



H. H. Brown. 

 Heckington, Feb. 23, 1842. 



Note — I drained some clay land in the year 1814 in this way, and very little of it 

 has required to be renewed. — Spencer. 



