Hence the motion of the air from both directions toward a stormy
district is deflected to the right side of the storm; and this gives
rise to that motion from right to left which is observed in the
hurricanes of the northern hemisphere.

To suppose, as many do, that regular winds, arising from constant
and extensive causes, can come into bodily conflict and preserve
their identity and original impetus for days, without immediate and
strongly impelling forces to sustain their motion, implies a
profound ignorance of mechanical science, and is little better than
those ancient superstitions which gave a personal identity to the
winds. The momentum of ordinary winds is a feeble force in
comparison with those forces of pressure and friction which
continually modify it. Hence sudden changes in the direction and
intensity of winds must primarily arise from similar changes in
these forces. But there are no known forces which change so suddenly,
except the pressure and latent heat of suspended vapor; and therefore
the fall of rain is the only adequate known cause of those
storm-winds which, interpolated among the gentler winds, keep the
atmosphere in perpetual commotion.

Storms have, however, certain habits and peculiarities, more or less
regular and distinct, which depend upon locality and season. And
this is what ought to be expected; for, though the storms themselves
are essentially anomalous, yet many of the causes which cooperate to
induce them are constant or periodic, while others are subject to
but slight perturbations. It is obvious that no more moisture can be
precipitated than has been evaporated, and that the winds only gain
suddenly by the fall of rain the forces which they have lost at their
leisure in the absorption of moisture. Thus the rage of the storm is