an ocean storm.

The revolution of the sun carries a spot across its face in about
fourteen days. After a lapse of as much more time, they often reappear
on the other side, changed but recognizable. They often break ont
or disappear under the eye of the observer. They divide like a
piece of ice dropped on a frozen pond, the pieces sliding off in
every direction, or combine like separate floes driven together
into a pack. Sometimes a spot will last for more than two hundred
days, recognizable through six or eight revolutions. Sometimes
a spot will last only half an hour.

The velocities indicated by these movements are incredible. An
up-rush and down-rush at the sides has been measured of twenty
miles a second; a side-rush or whirl, of one hundred and twenty
miles a second. These tempests rage from a few days to half a year,
traversing regions so wide that our Indian Ocean, the realm of
storms, is too small to be used for comparison; then, as they cease,
the advancing sides of the spots approach each other at the rate of
20,000 miles an hour; they strike together, and the rising spray
of fire leaps thousands of miles into space. It falls again into the
incandescent surge, rolls over mountains as the sea over pebbles, and
all this for eon after eon without sign of exhaustion or diminution.
All these swift succeeding Himalayas of fire, where one hundred
worlds could be buried, do not usually prevent the sun's appearing
to our far-off eyes as a perfect sphere.

[Page 94]
_What the Sun does for us._