584 THE PHILOSOPHY OF FARMING. 
draining, therefore, requires not the mere prac- 
tical skill of the persons employed therein—but 
a good general knowledge of the stratification of 
the districts in which drainage is required. 
And as philosophy takes nothing for granted ; 
as it is a science which consists entirely in a 
knowledge of facts founded upon natural prin- 
ciples ; and therefore submits all that is brought 
before it to tests ; whenever it enters upon a new 
path ; it therefore carries along with it as its 
guide, such tests as have been furnished by 
previous experience. Philosophy hence suggests 
—that when ground has to be drained, where the 
nature of the subsoil has not been ascertained 
that that nature be examined as a preparatory 
step. It gives the following data as guides to 
the inexperienced. If, when the soil has been 
carefully removed from an area of a few yards in 
extent, and the surface of the subsoil has been 
left to dry, water is found to accumulate within it, 
when dug into, then that subsoil is drainable ; 
and will draw water from the surface according 
to the depth dug, and the ground may be made 
perfectly dry by the usual kinds of drains; pro- 
vided those drains be laid sufficiently deep, and 
allowed a free discharge. Whereas, if after the 
