£38 COFFEE CULTIVATION AND MANURING. 
Dikoya, where the want of stones to create a natural 
drainage and ,a stiff sub-soil prevent the water from 
sinking dewn so fast as is required, and its accumu- 
lation in the sub-soil sours it. Soil, occasionally wet 
and occasionally dry, will improve in quality, turning 
blacker and more friable, while soil kept continually 
damp will turn into stiff clay. So the want of sub- 
soil drainage must be injurious to the coffee tree. 
At first sight Mr. Corbet’s plan of furrow draining 
(for it is evidently furrow drains Mr. Corbet means) 
seems the right thing to do. I have often thought 
of furrow draining, and thought how good a thing 
it would be to furrow-drain a stiff-bottomed field, 
and have even tried it on a small seale, but, as I ex- 
pected, could not afford to do it with coolies. Coolies 
do most things necessary on a coffee estate cheaper 
than European labour could accomplish the same task 
in their own country, most kinds of works at 50 per 
cent less than such works would cost in Hngland ; 
but notin cutting deep drains, that is a kind of work 
coolies will never be able to do at a reasonable rate. 
Furrow draining is thoroughly understood in England 
and Scotland, in Scotland more especially, and in 
furrow draining some rules are thought absolutely 
necessary to be followed—in all kinds of furrow drain- 
ing--to insure their answering the purpose for which 
ghey were intended, viz., the sub-soil. The first of 
ghese rules is to place the drain up and down the 
hills and not across it, as by placing the drain across 
the hill it will leak as much by the under side as 
it will drain from the upper. The second rule is that 
the depth shall cerrespond with the distance apart, 
4S feet is considered sufficient for drains 14 yards 
ayart. The third is that the drains be properly filled 
in, the bottom being provided with small stones, tiles, 
timber, or whatever may be considered most expedi- 
ent, that not being considered of so much consequence 
as the careful covering of the under layer with broken 
metal and over that a thatch of some kind to prevent 
earth from getting into the drain; water only may 
drain in below, but over this water must be pre- 
vented from getting into the drain by the surface, 
and to prevent this properly-worked clay must be 
put over the thatch and properly beaten down, and 
then the cutting filted up with earth rammed down, 
and the remaining earth spread over the field, and 
the furrow drain may be said to be finished. But 
another rule is, that all furrow drains be emptied 
into a leader properly built and not into any open ditch. 
‘* These rules will have to be complied with to en- 
sure success in draining. And what will be the cost? 
An acre of coffee will require about 200 yards of 
