Arcimis, Director of the Meteorological Institute, fell immediately in
front of the National Museum (Fig. 57). The phenomenon occurred at 9.30
A.M., in brilliant sunshine. The flash of the explosion was so dazzling
that it even illuminated the interior of the houses; an alarming clap of
thunder was heard seventy seconds after, and it was believed that an
explosion of dynamite had occurred. The fire-ball burst at a height of
fourteen miles, and was seen as far as 435 miles from Madrid!

In one of Raphael's finest pictures (_The Madonna of Foligno_) a
fire-ball may be seen beneath a rainbow (Fig. 58), the painter wishing
to preserve the remembrance of it, as it fell near Milan, on September
4, 1511. This picture dates from 1512.

The dimensions of these meteorites vary considerably; they are of all
sizes, from the impalpable dust that floats in the air, to the enormous
blocks exposed in the Museum of Natural History in Paris. Many of them
weigh several million pounds. That represented below fell in Mexico
during the shower of meteors of November 27, 1885. It weighed about four
pounds.

[Illustration: FIG. 58.--Raphael's Fire-Ball (_The Madonna of
Foligno_).]

These bolides and uranoliths come to us from the depths of space; but
they do not appear to have the same origin as the shooting stars. They
may arise from worlds destroyed by explosion or shock, or even from
planetary volcanoes. The lightest of them may have been expelled from
the volcanoes of the Moon. Some of the most massive, in which iron
predominates, may even have issued from the bowels of the Earth,
projected into space by some volcanic explosion, at an epoch when our
globe was perpetually convulsed by cataclysms of extraordinary violence.
They return to us to-day after being removed from the Earth to distances
proportional to the initial speed imparted to them. This origin seems
the more admissible as the stones that fall from the skies exhibit a
mineral composition identical with that of the terrestrial materials.

[Illustration: FIG. 59.--A Uranolith.]

In any case, these uranoliths bring us back at least by their fall to
our Earth, and from henceforward we will remain upon it, to study its
position in space, and to take account of the place it fills in the
Universe, and of the astronomical laws that govern our destiny.

CHAPTER VIII

THE EARTH

Our grand celestial journey lands us upon our own little planet, on this
globe that gravitate