objects
this
double
process
ordinarily
works but
unobtrusiveeffects.
Only in a
few cases,
among
which that
of a cloud
is the
most
familiar,does
the
conflict
produce
rapid and
marked
transformations.
One of
thesefloating
bodies of
vapour
expands
and
dissipates,
if the
amount of
molecularmotion
it
receives
from the
Sun and
Earth
exceeds
that which
it loses
byradiation
into space
and
towards
adjacent
surfaces;
while,
contrariwise,if,
drifting
over cold
mountain-tops,
