he
origin of the meteoric showers of November and August, and especially
those of November?' Many readers know that for some years past great
numbers of falling-stars, or showers of meteors, have been observed
periodically in November: the fall seen in the United States in
1834--when, as is estimated, more than 240,000 stars fell as thick as
snow-flakes, in the space of nine hours--being the most remarkable
hitherto known. The explanation is, that the zodiacal light is a
nebulous body revolving round the sun, and arrives at its aphelion on
the 13th November in that part of the earth's orbit which the earth
then reaches, and, coming into contact with our atmosphere, portions
of the nebulous matter are detached, and, taking fire as they pass
through, appear to us as shooting-stars. This explanation of the
phenomenon in question is one not hastily conceived; the reasoning on
which it is founded is altogether satisfactory, as well with regard to
the movement of the nebulous matter, as to that of the earth.

Professor Olmsted, in a communication addressed to the 'American
Association for the Advancement of Science,' sums up his views as
follows:

'1. The zodiacal light, as we have found, in our inquiry into its
nature and constitution, is a _nebulous body_.

'2. It has a revolution round the sun.

'3. It reaches beyond and _lies over the earth's orbit_ at the time of
the November meteors, and makes but a small angle with the ecliptic.

'4. Like the nebulous body, its periodic time is commensurable with
that of the earth, so as to perform a certain whole number of
revolutions while the earth performs one, and thus to complete the
cycle in one year, at the end of which the zodiacal light and the
earth return to the same relative position in space. This necessarily
follows from the fact, that at the same season of the year it occupies
the same position one year with another, and the same now as when
Cassini made his observations nearly 170 years ago.

'5. In the meteoric showers of November, _the meteors are actually
seen to come from the extreme portions of the zodiacal light_, or
rather a little beyond the visible portions.'

There is much that is suggestive in this summary, and, as we said at
the commencement, the subject is one of a nature to stimulate inquiry
and research, and to lead to further explanations of cosmical
phenomena. M. Mathieson's observations, published in the _Comptes
Rendus_ of the Academie des S