a 
1903] VEGETATION OF THE BAY OF FUNDY MARSHES 283 
water, but is worse than the average for aeration. For the latter 
reason it is adapted only for vegetation with superficial or 
extremely slender roots, and such the grasses are, while thick- 
rooted forms, like trees or root crops, needing better aeration, 
cannot grow, or at least cannot thrive, there. 
An extremely important property of soils is their power of 
circulating water and mineral matters. Every particle of moist 
soil is surrounded by its film of hygroscopic (and capillary) 
water holding mineral matters in solution, and these films are in 
continuity. But the relations of these films to the soil particles 
and to one another are such that they are, as it were, in a state of 
unstable equilibrium, so that when water is removed (if not too 
rapidly) from them at any place, it is restored from neighboring 
particles, which draw upon others yet more remote, and so on 
until the equilibrium is restored. And this adjustment is the 
more perfect the finer the soil. When thus traveling the water 
Carries its dissolved minerals with it. Moreover, owing to the 
operation of the process of diffusion, the minerals are tending to 
distribute themselves through the films of water even when these 
are at rest, from the places where the minerals are more abundant 
to the places where they are lessso. The law of water and min- 
eral movement in soils may be thus expressed: lu a homogeneous 
sol the water tends to distribute itself evenly throughout the mass, and 
the soluble minerals tend to distribute themselves evenly throughout the 
water; a draft at one place upon water and minerals therefore ts a draft 
upon the entire mass if the rate of removal be not more rapid than the 
equilibrium-restoring power of the sotl, which ts the higher the finer the 
sol, It hence follows that in a homogeneous or nearly homo- 
geneous soil, the plants, if their demands be not greater than the 
_power of the soil to distribute the water, are not dependent for 
water and minerals simply upon such parts of the soil as can be 
reached by their roots, but can draw upon the entire mass, the 
more readily the finer the soil is. Here, I believe, we find the 
explanation of the lasting quality of the fertility of these marshes 
when reclaimed; it is due to their depth in combination with 
their homogeneity, aided by the great water-holding and trans- 
ferring power given by their fineness of soil. The abundant water 
