ly forty cases of rain, in one hundred, affected the
apparatus with both kinds_ of electricity; sometimes with an
interval, in which no rain fell; and so, that a positive shower was
succeeded by a negative; and, _vice versa_; at others, the two kinds
alternately took place during the same shower; and, it should seem,
_with a space of non-electric rain between them_."

Howard attributes, with great apparent probability, the successive
differences in the electrical character of the rain, to the passage of
different portions of the cloud, having different polarity, over the place
of observation. So _positive hail_, and _negative rain_ fall in _parallel
bands_ from the same cloud. Many such instances are on record. It should
be remembered that he is describing the phenomena in the showery climate
of England.

But the most decisive, perhaps, as well as practically important evidence
of the influence of magnetism, or magneto-electricity, in meteorological
phenomena, is derived from the action of storms. My observation has been
limited, for my life has been, and must be, a practical one. But, subject
to future, and I hope speedy corroboration, or correction, by extensive
systematic observation, I think I may venture to divide all storms into
four kinds:

1. Those which come to us from the tropics, and constitute the class
investigated by Mr. Redfield. That these are of a magneto-electric
character is evident. They originate near the line of magnetic intensity,
over, or in the vicinity of, the volcanic islands of the tropics; are
largely accompanied by electrical phenomena; extend laterally as they
progress north; induce and create a change of temperature in advance of
them, and do not abate until they pass off over the Atlantic to the E. or
N. E., and perhaps not until they reach the Arctic circle. Their extensive
and continued action is not owing to any mere _mechanical agency_ of the
adjoining passive air, or other supposed currents, originated, no man can
tell how, but they concentrate upon themselves the local magnetic currents
as they pass over and intersect them, and, by their inductive action upon
the surface-atmosphere, in different directions, attract it under them,
and within their more active influence. Here the action of the magnetic
currents is probably the primary cause, but the power of the storm to
concentrate upon itself the new magnetic currents which it intersects as
it enters each