Flashes of electricity have been detected, during warm, close weather,
issuing from some species of plants. The Tuberose and African Marigold
have been seen to emit these mimic lightnings. (Goethe is the
authority for this.) To atmospheric electricity we doubtless owe the
coruscations of the Aurora, one of the most beautiful of our meteors.

The usual forms of lightning are the zigzag or forked sharply
defined,--the sheet-lightning, illuminating a whole cloud, which it
seems to open,--heat-lightning, not emanating from any cloud, but
apparently diffused through the air and without report. There are also
fireballs which shoot across the sky, leaving a train often visible
for seconds and minutes. These last, when they project any masses to
the earth, are termed aërolites.

Atmospheric electricity has much to do with the distribution of rain,
the precipitation of vapor, the condition of our nervous system, and,
according to Humboldt, with the circulation of the organic juices.
Atmospheric electricity has heretofore been a great obstacle to the
success of the Magnetic Telegraph, and curiously disturbs its
operation; but there has recently been invented an instrument called a
Mutator, which is connected with the wires, and carries off all the
disturbing influences of the atmosphere without interfering with the
working current. On the other hand, artificially created electricity
has led to important advances in many of the arts and sciences.

Ice is water frozen under a very curious and peculiar law. Hail is the
congelation of drops of rain in irregular forms, always sudden,--by
some attributed to electricity and currents of air violently rarefied
by it, and by others to rain-drops falling through a cold stratum of