Page:Popular Science Monthly Volume 4.djvu/783

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Journal of Science and the Arts, has wellnigh demonstrated that dry land existed in the Lower Silurian age. He communicates the discovery of two small specimens representing branches or small stems of a species referable to Sigillaria, and found on Longstreet Creek, near Lebanon, Ohio, in clay-beds positively referable to the Cincinnati group of the Lower Silurian. With the exception of these Lebanon specimens, the geological formations of the United States have not afforded as yet any records of plants earlier than those of the Lower Devonian.

The Uses of Bees' Wings.—At the lute Convention of Bee-Keepers at Louisville, D. L. Adair read an essay on the various uses of the bee's wings, in which he holds that, besides flying, the wing of the bee serves two or three other important ends. The horny frame, upon which the fine membrane of the wings is stretched, is composed of hollow tubes of a hard substance called chitine. These tubes are double, being one tube inside of another. The inner ones are extensions of the tracheæ, through which the air circulates in breathing; between this and the other tube is a space through which the blood circulates. The blood is brought in contact with the air through the thin walls of the air-tubes, just as the air and blood are brought together in the human lungs, and with the same effect.

The nervous filaments in like manner pass to the wings; they follow the respiratory tubes and all the fine venations of the wing, terminating in every part of its surface in papillæ, which in all animals are the vehicles through which sensations are perceived. Hence we may infer that the wings are the organs of some sensation. Are these nerve-filaments intended merely for noting tactile sensations? Mr. Adair is of the opinion that by means of them the bee is made conscious of odors. "Some naturalists have suggested the antennæ as the organs of smell; but, as they appear to be poorly adapted to perform such an office, it is just about as likely that they smell with them as that they see with them. Invisible particles emanating from odorous bodies, coming in contact with the olfactory nerves, produce the sense of smell. These atoms are mixed with and floating in the air, and, in order to collect them, a considerable volume of air must be made to pass over their surfaces—a thing which the wings certainly accomplish in an eminent degree."

The sense of hearing in bees has never been localized by naturalists, though some have supposed that the antennæ are the organs of this sense also. "What appendage of the bee," asks Mr. Adair, "would be better suited to receive sound-vibrations than the thin, stiff membranes composing the wings?"

The Lignite-Beds of the Rocky Mountains.—The opinion having been advanced that the so-called lignite-beds of the Rocky Mountains have been formed by the heaping of drifted materials, and not by growth in situ, Mr. L. Lesquereux replies as follows, in Silliman's Journal, to one of the arguments urged in favor of the opinion—viz., that the under-clays of the lignite-beds have no roots: "I can say," he writes, "from repeated and personal observations, that most of the lignite-beds of the West, which have passed under my examination, have the under-clays full of rootlets or of roots of the floating plants, which were the first, generally at least, to contribute to the formation of the bed of combustible material by their débris. At the Raton Mountains, at Cañon City, at Gehrung's, near Colorado, at Golden, Marshall, Black Butte, etc., the coal is everywhere underlaid by chocolate-colored shale, often a compound of these roots or rootlets, so compact, indeed, that they cannot be determined, nor their forms distinctly recognized. Of coarse, the under-shales do not contain any roots (true roots of trees); the coal of the carboniferous, too, never has any, for the good reason that trees do not grow in water, and that they only invade peat-bogs when the ground is solid enough to support them. And even then the roots grow horizontally, and do not descend deep into the matter which, generally impregnated by water, is to a degree inaccessible to atmospheric influence.

The so-called roots of the clay-beds of the carboniferous measures, or the Stigmaria, are not roots, but floating leaves. And even their cylindrical stems are rarely