ower of 1867 was seen. Even in
the following year the great shoal had not entirely passed, and since
then a few stragglers along the route have been encountered at each
annual transit of the earth across this meteoric highway.

The diagram is also designed to indicate a remarkable speculation which
was put forward on the high authority of Le Verrier, with the view of
explaining how the shoal came to be introduced into the solar system.
The orbit in which the meteors revolve does not intersect the paths of
Jupiter, Saturn, or Mars, but it does intersect the orbit of Uranus. It
must sometimes happen that Uranus is passing through this point of its
path just as the shoal arrives there. Le Verrier has demonstrated that
such an event took place in the year A.D. 126, but that it has not
happened since. We thus seem to have a clue to a very wonderful history
by which the meteors are shown to have come into our system in the year
named. The expectations or a repetition of the great shower in 1899
which had been widely entertained, and on good grounds, were not
realised. Hardly more than a few meteors of the ordinary type were
observed.

Assuming that the orbit of the August meteors was a parabola,
Schiaparelli computed the dimensions and position in space of this
orbit, and when he had worked this out, he noticed that the orbit
corresponded in every particular with the orbit of a fine comet which
had appeared in the summer of 1862. This could not be a mere matter of
accident. The plane in which the comet moved coincided exactly with that
in which the meteors moved; so did the directions of the axes of their
orbits, while the direction of the motion is the same, and the shortest
distance from the sun to the orbit is also in the two cases identical.
This proved to demonstration that there must be some profound physical
connection between comets and swarms of meteors. And a further proof of
this was shortly afterwards furnished, when Le Verrier had computed the
orbit of the November meteors, for this was at once noticed to be
precisely the same as the orbit of a comet which had passed its
perihelion in January, 1866, and for which the period of revolution had
been found to be thirty-three years and two months.

Among the Leonids we see occasionally fireballs brighter than Venus, and
even half the apparent size of the moon, bursting out with
lightning-like flashes, and leaving streaks which last from a minute to
an hour or more.