102 SECTIONAL ADDRESSES. 
to be growing clear that the upraising no less than the destruction of land 
masses, the boundaries no less than the spread of natural regions, are in 
their origin, at any rate in the present and recent geological epochs, 
mainly due to the hydrosphere. In this discussion I have not dealt with 
the special features of the marine natural regions; they are obviously 
phenomena of the hydrosphere. 
Consider now the results that follow from the existence of natural 
regions. We can imagine a world without definite natural regions, all 
sown over, let us say, with isolated peaks, like volcanic cones, and the 
liquid water gathered into innumerable small lakes, so that the lowland 
became a world-wide net of connected fertile strips with peaks and lakes 
in the meshes. In such a world it is difficult to see how a vast number of 
contrasted species could arise and flourish, for there would be no breaks 
in blood continuity behind which local varieties could be isolated and 
fixed, and no broad areas of uniformity where mature species could 
become dominant. Some day, in the fulness of knowledge, a biologist 
and a geographer will perhaps collaborate to show that our actual catalogue 
of species, in their grouped families and orders, is correlated with a world 
in which you have a single ocean, one great and three minor contiuents, a 
few vast plains and plateaux, a few high dividing ranges of mountain, 
and many small islands, peninsulas, valleys, lakes, oases. The effect of 
momentum from past geographies would, of course, have to be taken into 
account. 
There are two essential facts to be remembered in regard to the hydro- 
sphere. The first is that it conveys and stores energy and is not a source 
of energy. The energy which works within it comes for the most part 
either direct from the sun or is controlled by life. (Will you, for shortness, 
allow me to bracket the moon’s tidal pull with the sun’s energy?) The 
geographical significance of Life les in its action in mass. That fact is 
obvious in the cases of rocks made of coral and coal made of trees. It is 
true no Jess where the life is carried in a multitude of mobile individuals. 
The higher beings act gregariously by impulse. They are attracted or 
repelled by ideas which they can communicate to one another. No one 
who has watched a flock of birds in flight but must agree to that statement. 
The Gadarene swine were another case in point. In human affairs the 
run on a bank, or the march of an army, or the digging of a canal is com- 
parable. 
A second characteristic of the hydrosphere is that it is a closed system. 
This follows from the facts that it is a sphere, that it is liquid or ever 
returning to liquid, and that, so far as we know, the amount of water is 
not appreciably increasing or diminishing. It is the medium, therefore, 
of a single dynamic system. Nothing can happen at any point within it 
which has not repercussions at every other point, although the internal 
elasticity of the system is fortunately mitigated by the rising and falling 
of the liquid surfaces and the passage of the liquid into the gaseous and 
solid states. Theoretically it is true that no cape is worn into a new form 
owing to a change in the impact of a sea current but a set of changes, nine- 
pin-like, is started which goes the round of all the coasts of the world, 
current changing shape and shape reacting on current. This statement 
carries with it the implication that every natural region is part of the 
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