78 Mole-draining and the Renovation of Old Pipe Drains. 
The question then arises whether the field must be com- 
pletely redrained or whether the old drains can be made to 
work, i.e ., can the old mains be made serviceable? Very often 
if the old drain mouths are taken up, cleaned and re-laid for 
a few yards back the drain will work again. It is nearly 
always worth while to clear a ditch up to an old stone drain, 
as water so often finds its way in the wet times down 
them, but it is a waste of time and labour to renovate horse- 
shoe drains without a bottom, or with a loose bottom, and this 
also applies to 1 in. round pipes. Nor as a rule is it any good 
trying to renovate 2 in. pipes coming direct into the ditch, 
though sometimes a new main properly connected to the old 
2 in. pipes may effect a cure. 
Having found the mouth of the drain, if it be a 3 in. or a 
4 in. or even a larger round pipe, it is advisable to open the 
main in several places for examination. If the pipe should 
not be too full of dirt, or if the dirt be not too hard, it can 
sometimes be cleaned out by means of 2 ft. bamboo drain rods, 
or other rods that will not come unfastened in the drain, or 
even by a wire. The rods must be worked from openings in the 
drain at about every 20 yards. They should be used from the 
mouth upwards when the drain is full of water ; working the 
rods down with the water often causes a new stoppage as the 
displaced mud cannot get away. If the drain is too full of 
dirt to admit of its being easily cleaned out by rods, it is best 
abandoned unless it is within 2 ft. 6 in. of the surface when 
the pipes may be dug out, cleaned, and relaid at a less cost than 
carrying out entirely new work, but if the drain is deeper than 
2 ft/ 6 in. it will generally be found cheaper and more satis- 
factory to buy new pipes and make new drains. 
So far no mention has been made of a very common cause 
of waterlogged land chiefly found on arable land, but often, 
too, on pasture land ; on arable fields by continual ploughing 
and by the tread of the horses an impervious pan is formed 
just under the ploughed soil, through which the water can 
only very slowly, if at all, find its way. Another common 
cause is that the land has been drained too deep. Thousands of 
acres were drained 4 ft. deep about forty years ago with money 
borrowed from one of the societies formed under the Lands 
Improvement Acts. These drains had to be passed by an 
inspector from the Board of Agriculture and consequently 
have come to be known as Government drains. These so- 
called Government drains have in many instances quite failed 
to take away the surface water, partly because a pan has 
formed as mentioned above and partly because the surface 
water cannot get through the clay into the drains after the 
moved soil has become set over them. I have examined a 
