ys previously. In
reality, the rotation of the Sun occupies twenty-five and a half days,
but strangely enough this globe _does not rotate in one uniform period_,
like the Earth; the rotation periods, or movements of the different
parts of the solar surface, diminish from the Sun's equator toward its
poles. The period is twenty-five days at the equator, twenty-six at the
twenty-fourth degree of latitude, north or south, twenty-seven at the
thirty-seventh degree, twenty-eight at the forty-eighth. The spots are
usually formed between the equator and this latitude, more especially
between the tenth and thirtieth degrees. They have never been seen round
the poles.

Toward the edges of the Sun, again, are very brilliant and highly
luminous regions, which generally surround the spots, and have been
termed _faculae_ (_facula_, a little torch). These faculae, which
frequently occupy a very extensive surface, seem to be the seat of
formidable commotions that incessantly revolutionize the face of our
monarch, often, as we said, preceding the spots. They can be detected
right up to the poles.

Our Sun, that appears so calm and majestic, is in reality the seat of
fierce conflagrations. Volcanic eruptions, the most appalling storms,
the worst cataclysms that sometimes disturb our little world, are gentle
zephyrs compared with the solar tempests that engender clouds of fire
capable at one burst of engulfing globes of the dimensions of our
planet.

To compare terrestrial volcanoes with solar eruptions is like comparing
the modest night-light that consumes a midge with the flames of the fire
that destroys a town.

The solar spots vary in a fairly regular period of eleven to twelve
years. In certain years, _e.g._, 1893, they are vast, numerous and
frequent; in other years, _e.g._, 1901, they are few and insignificant.
The statistics are very carefully preserved. Here, for instance, is the
surface showing sun-spots expressed in millionths of the extent of the
visible solar surface:

1889 78
1890 99
1891 569
1892 1,214
1893 1,464
1895 974
1896 543
1897 514
1898 375
1899 111
1900 75
1901 29
1902 62

The years 1889 and 1901 were _minima_; the year 1893 a _maximum_.

It