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IV.—On the Amount of Sand brought up by Lobworms to the Surface

Published online by Cambridge University Press:  01 May 2009

Charles Davison
Charles Davison
Affiliation:
Mathematical Master at King Edward's High School, Birmingham.
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Extract

Ten years ago Charles Darwin published his last work, the result of more than forty years' observations on the habits of earthworms and the rate at which they bring up soil to the surface. To ascertain this rate, he made use of two methods. In the first place he measured the rate at which layers of lime or cinders were covered over by the spread-out castings of worms; and, later, he collected and weighed all the castings thrown up over a definite area within a given time. As is well known, the general result of his investigation was greatly to exalt our ideas of the importance of earthworms and of the work they do upon the surface of the land.

The work performed by lobworms on the surface of tidal sands seeming not less worthy of study, I made some observations on the subject during a short stay in Holy Island last August.

Type
Original Articles
Information
Geological Magazine , Volume 8 , Issue 11 , November 1891 , pp. 489 - 493
Copyright
Copyright © Cambridge University Press 1891

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References

page 489 note 1 See “A Faulted Slate” byTeall, J. J. Harris, (Geol. Mag. 1884, pp. 1, 2.Google Scholar

page 489 note 2 “The Formation of Vegetable Mould, through the action of Worms, with Observations on their Habits,” 1881.

page 491 note 1 I have not been able to learn anything decisive on this point, but I was informed by a resident on Holy Island that the castings appeared to be quite as numerous there in winter as in summer.

page 491 note 2 Mr. Darwin has calculated the amount of soil brought up by earthworms in four cases, one of these being near Nice and the other three in England. The results are 14·58, 18·12, 7·56, and 16·1 tons per acre every year (pp. 160–169). The average of these estimates being 14·09 tons per acre, it follows that the weight of sand brought up by lobworms is 136 times the weight of soil brought up by earthworms over an equal area in the same time.

page 492 note 1 DrCarpenter, W. B., “Zoology” (1867), vol. ii. p. 300.Google ScholarDrJohnston, G., “ A Catalogue of the British Non-parasitical Worms in the Collection of the British Museum ” (1865), p. 230.Google Scholar