The vortex, in its passage round the earth, may only meet with a few
localities favorable for producing a very violent storm; but these
nuclei will generally be connected by bands of cloudy atmosphere; so
that could we view them from the moon, the earth would be belted like
the planet Jupiter. There is reason to suspect, also, that there are
variations in the energy of the ethereal motions, independent of the
conditions of the earth and its atmosphere, which affects even the
radial stream of the sun. For the zodiacal light, which is caused by
this radial stream, is at times much more vivid than at others. Also in
the case of the aurora, on our own globe. On this point there is much to
say, but here is not the place. The conditions favorable for the
production of a storm at the _central_ passage of a vortex, are a
previous exemption from excitement _ceteris paribus_, a high temperature
and dew point, a depression of the barometer, and local accumulation of
electric tension, positive or negative; and these are influenced by the
storms in other places controlling the aerial currents, and thus
determining the atmosphere of the place.