I 
Mole-draining and the Renovation of Old Pipe Drains. 83 
Mole drains must follow the natural fall of the surface of 
the ground (Fig. 6), and they must also follow either the furrow 
or the ridge (Fig. 7). The reason of this, is, of course, that the 
drain itself will follow the surface of the land exactly, and a 
drain cut across the ridge and furrow would reproduce each rise 
and fall, which would obviously be fatal (Fig. 8). 
In Fig. 5 the method of dealing with mole drains over 
10 chains long is indicated, new eyes being dug and the two 
ihole drains connected by means of 2 in. pipes in the eyes. 
Mole draining with engines can only be done when the 
surface is hard enough to carry the engines, and when the 
subsoil is wet enough to allow the mole plough to work easily, 
and to allow of the glazing of the drain. These conditions are 
usually to be found at the end of April and beginning of May, 
and only very rarely indeed in the autumn. In April and May 
the winter sown crops are well up, and generally the spring 
crop is sown. The ideal crop for mole-draining on is, of course, 
seeds, or stubble not yet ploughed, but in actual practice very 
little damage is done whatever the crop may be. I have drained 
a field with winter beans 15 in. to 18 in. high with hardly any 
damage, and I have constantly drained wheat fields. A dead 
fallow field can be drained if the clods are not too big. In all 
cases where mole-draining is to be done, if the surface is dry 
enough for the engines it is not advisable to defer the draining 
merely on account of possible damage to the crop. 
If the depth is not more than 2 ft. 3 in. and the pull 9 or 
10 chains, then about fifteen acres should be drained in a day 
provided that everything is ready for the work — /.<?., mains, 
eyes, coal, water, &c. 
As to drain mouths : Built-up expensive blue brick mouths 
fall sooner or later into the ditch, or are left as islands. Dry 
