On Drahnnff. 
427 
and regular fall ; and where that is not the case the drainage will 
bo imperfect. The materials may now be laid down near the side 
of the drains ;* and the drainers are to commence cutting the 
main-drain, beginning at the lowest point, and to such a depth 
that the top of the conduit shall lie on a level with the floor of the 
smaller drains : so that in heavy falls of rain, or from other causes, 
if the main should be nearly full, the water does not How back in 
the smaller drains. In performing this part of the work, care 
should be taken to cut the bottom of the drain no wider than the 
tile, and a little hollowed out at the bottona to receive the crown 
of it ; and the sides so that when the upper tile is laid, it cannot 
move from its bearing on the lower tile. This may not be prac- 
ticable where there are many sand-veins, &c. ; but on the strong 
subsoils of this and surrounding counties, the drains can be cut to 
any required width. In no instance, on strong subsoils, should I 
recommend for main-drains a single tile laid upon a sole : first, 
because the saving of expense is comparatively trifling ; and, 
secondly, because in all sewers or water-courses, the lodgment, or 
accumulation of sediment, is much greater on a flat wide floor 
than where the bottom is an inverted arch. After cutting as 
much of the main-drain as can safely be done without the sides 
falling in, the drainer or tile-layer is to commence at the lower end 
to lay in the tiles, first laying two tiles on the floor of the drain, 
and then one on the top, resting equally upon the bottom two, 
and so in this way to break the joinings throughout the whole 
length of drain ; and, where circumstances will permit, I prefer 
that the whole length of the drain should have the tiles laid before 
it is filled in. If the minor drains are of great length, the tiles in 
the main, where they cross, should have a small piece cut off the 
crown of the arch (which should be done at the tile-works), to 
admit the water to discharge more freely into it. When the whole 
of the main-drain is laid, and seen to have a regular fall, it may 
be filled in, except where the minor drains cross it. With the 
minor drains commence where they cross the main, which having 
been opened with the plough 10 inches deep, two draws (one 
with a spade 10 inches, and one with the draining-tool 12 inches) 
will, with the work as previously directed to be done, make the 
drains from 32 to 36 inches deep ; and if the men are careful to 
* In laying down draining-tiles it is advisable lo avoid unnecessarily 
exposing them to the action of wet and severe frost. I have seen white 
and red tiles well burnt, when struck together giving a tine metallic sound, 
and which would have lasted for ages in the bottom of a drain, break to 
pieces if they have been frozen by very severe frost, as they lay in shallow 
water in the bottom of the furrows; and the same, it is well known, will 
take place with many descriptions of earthenware of (he best cpiality. 
