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Page:Popular Science Monthly Volume 18.djvu/634

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THE POPULAR SCIENCE MONTHLY.

I have already referred to it as a matter of considerable interest, that a large proportion of some coal is made up of crushed vegetable cells; but that is not all—a still more wonderful fact remains to be noticed: The microscope, prying into all the little corners and secret places of Nature, declares that the pitchy parts of most bituminous coal are composed almost entirely of little spherical bodies, microscopic in size—so minute, indeed, that hundreds of them together might well be disregarded as "the small dust of the balance"—and yet so numerous that great coal-seams often appear to be made up of little else. Large numbers of them are often found huddled together in small round sacs

PSM V18 D634 Lepidodendron compared with club moss.jpg
Fig. 8.—Lepidodendron compared with Clue-Moss: a, club-moss; b, a scale enlarged; c, microspores; d, macrospores; x, lepidostrobus; y and z, the scales containing spores; m, microspores; n, macrospores.

of peculiar appearance. We are indebted to the patient labor of a number of observers for the fact that the smaller granules are the spores or seeds of some plant of inferior organization, and the larger sacs are fruit-cases in which the spores were developed. The whole history of this fruit, the manner in which it was produced, its relation to the stem and leaves of the plant to which it belongs, even its fertilization and development, have all been carefully worked out with an