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.

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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 hothouses in our cold climate, are even in the semi-tropical region of Key West, on the Florida Reef, seen to grow enormously in length.

[Illustration:  THE CANDELABRA CACTUS—­CEREUS GIGANTEUS.]

We cultivated several species of the more interesting forms during a residence on the reef.  Our brick house, two stories in height, was entirely covered on a broad gable end, the branches more than gaining the top.  There is a regular monthly growth, and this is indicated by a joint between each two lengths.  Should the stalk be allowed to grow without support, it will continue growing without division, and exhibit stalks five or six feet in length, when they droop, and fall upon the ground.