The formation of vegetable mould, through the action of worms (1881)
THE FORMATION
OF
VEGETABLE MOULD,
THROUGH THE
ACTION OF WORMS,
WITH
OBSERVATIONS ON THEIR HABITS.
By CHARLES DARWIN, LL. D., F.R.S.
WITH ILLUSTRATIONS
LONDON:
JOHN MURRAY, ALBEMARLE STREET.
1881.
The right of Translation is reserved.
LONDON:
PRINTED BY WILLIAM CLOWES AND SONS, LIMITED,
STANFORD STREET AND CHARING CROSS.
CONTENTS.
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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Page 1–7 |
HABITS OF WORMS.
HABITS OF WORMS.—continued.
THE AMOUNT OF FINE EARTH BROUGHT UP BY WORMS TO THE SURFACE.
Rate at which various objects strewed on the surface of grass-fields are covered up by the castings of worms—The burial of a paved path—The slow subsidence of great stones left on the surface—The number of worms which live within a given space—The weight of earth ejected from a burrow, and from all the burrows within a given space—The thickness of the layer of mould which the castings on a given space would form within a given time if uniformly spread out—The slow rate at which mould can increase to a great thickness—Conclusion 129–175
THE PART WHICH WORMS HAVE PLAYED IN THE BURIAL OF ANCIENT BUILDINGS.
THE ACTION OF WORMS IN THE DENUDATION OF THE LAND.
Evidence of the amount of denudation which the land has undergone—Subaerial denudation—The deposition of dust—Vegetable mould, its dark colour and fine texture largely due to the action of worms—The disintegration of rocks by the humus-acids—Similar acids apparently generated within the bodies of worms—The action of these acids facilitated by the continued movement of the particles of earth—A thick bed of mould checks the disintegration of the underlying soil and rocks—Particles of stone worn or triturated in the gizzards of worms—Swallowed stones serve as millstones—The levigated state of the castings—Fragments of brick in the castings over ancient buildings well rounded. The triturating power of worms not quite insignificant under a geological point of view 230–258
THE DENUDATION OF THE LAND—continued.
CONCLUSION.
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315–326 |
This work was published before January 1, 1929, and is in the public domain worldwide because the author died at least 100 years ago.
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