Chap. III.] DOWNWARD GROWTH OF THE ROOT. 
opposite direction,—that is, towards the zenith. 
And why the root should obey, and the stem 
disobey, the otherwise universal law of gravity, 
would still puzzle our philosophy, as I said 
before. 
But difficult as it would be to swallow the 
*fact , that gravity should cause part of a plant to 
go with it and part against it, this is only half 
of what we have to swallow. For, actually, the 
whole vertical growth of plants is against gra¬ 
vity; and to say that gravity causes that growth 
against itself, is as contradictory as to say that 
darkness causes light. But, in fact, gravity acts 
as much against the descent of the root in earth , 
as against the ascent of the stem in air. Gra¬ 
vity is a fine word, and means weight. Attrac¬ 
tion of gravitation is a fine term, and means 
the attraction of weight: and, loosely speaking, 
it may be said, that within this world the sole 
effect of gravity or weight is, that the heaviest 
things have a tendency to get lowest; that is, 
that (though we know not how or why) they 
are the most drawn towards the centre of the 
earth, and, consequently, that the lightest things 
have a tendency to get highest, — that is, that, 
where there is perfect facility of movement in all 
directions, as in fluids, the lightest things are 
