THE FORMATION OF PLANTATIONS. 99 
and flourishing, the soil itself is in a fairly good condition, both 
chemically and mechanically, or at least so far as uncultivated 
ground can be expected to be. But the natural vegetation usually 
consists of plants best fitted to exist under those conditions of soil 
and climate in which they are found, and therefore the fact that 
the indigenous plants are thriving is no criterion by which we 
can prove that the trees we wish to plant there will thrive too, 
unless we know that the latter thrive under the same conditions as 
the former. If we know this, we can assume that the ground is 
in a comparatively fit condition for the plants we wish to intro- 
duce, and draining is therefore unnecessary, but where the 
vegetation indicates a condition of soil known to be unsuitable 
to the plants we wish to stock the ground with, then we must 
endeavour to remedy this unfavourable condition if possible. 
On the other hand, when the soil is in a sour, unhealthy condi- 
tion, the vegetation invariably indicates it. If we notice the 
heather growing on a wet piece of moorland, with an underlying 
stratum of moor-pan, we usually find it stunted, sickly, and covered 
with lichens, so that we come to the conclusion that something is 
necessary to put it in a more satisfactory state, and the removal of 
the superfluous moisture will be the first consideration. 
The first point to be considered in commencing to drain, is the 
outlet which will have to carry off the whole of the discharge from 
the drains connected with it, and if possible this should always 
lead into a natural water-course or burn, as all further trouble is 
thereby avoided in getting rid of the water, providing the natural 
channel is sufficiently wide and deep to carry off the additional 
water. It is not necessary for all the drains to have the same 
outlet, as in hilly and unduiating ground this would be practically 
impossible ; but on flat ground, or where the fall or slope is very 
slight, the lowest part of the ground must be the point for the 
outlet, which should be carefully ascertained by means of the 
theodolite and levelling rods, as guess-work is often very risky in 
regard to this point. The outlet having been decided on, a main 
drain (or several, if required) should be cut from it to the farthest 
extremity of the ground that requires draining, giving it a few 
inches more depth than the sub-mains running into it. The main 
drain, and all others in fact, should be perfectly straight if the 
surface of the ground permits, but if not, it should take such a 
course as will ensure a gradual and uniform fall from its com- 
mencement to the outlet, which must depend upon the slope of 
