d; enough, however, is known
to give foundation for the assumption that meteorites and comets are not
very dissimilar.

The light of a meteorite is not seen until it enters the atmosphere of
the earth, but falling meteorites can be vaporized by electricity, and
the light emitted by their constituents be then examined with the
spectroscope. The light of comets can be directly examined, and it
reveals the presence in those bodies of sodium, carbon, and a few other
well-known substances. He would put a piece of meteorite in the electric
arc to see what light it would give; he had never tried the experiment
before. The lights of the theater were then turned down, and the
discourse was continued in darkness; among the most prominent lines
visible in the spectrum of the meteorite, Professor Dewar specified
magnesium, sodium, and lithium. "Where do meteorites come from?" said
the lecturer. It might be, he continued, that they were portions of
exploded planets, or had been ejected from planets. In this relation, he
should like to explain the modern idea of the possible method of
construction of our own earth. He then set forth the nebular hypothesis
that at some long past time our sun and all his planets existed but as a
volume of gas, which in contracting and cooling formed a hot volume of
rotating liquid, and that as this further contracted and cooled, the
planets, and moons, and planetary rings fell off from it and gradually
solidified, the sun being left as the solitary comparatively uncooled
portion of the original nebula. In partial illustration of this, he
caused a little globe of oil, suspended in an aqueous liquid of nearly
its own specific gravity, to rotate, and as it rotated it was seen, by
means of its magnified image upon the screen, to throw off from its
outer circumference rings and little globes.

* * * * *

CANDELABRA CACTUS AND CALIFORNIA WOODPECKER.

By C.F. HOLDER.

One of the most picturesque objects that meet the eye of the traveler
over the great plains of the southern portion of California and New
Mexico is the candelabra cactus. Systematically it belongs to the Cereus
family, in which the notable Night-blooming Cereus also is naturally
included. In tropical or semi-tropical countries these plants thrive,
and grow to enormous size. For example, the Cereus that bears those
great flowers, and blooms at night, exhaling powerful perfume, as we see
them in hothous