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Volcanic Dust in the Atmosphere and the Interpretation of African Eclipse Traditions

Published online by Cambridge University Press:  13 May 2014

Ronald W. Davis*
Affiliation:
Western Michigan University

Extract

The purpose of this discussion is to call attention to the presence at various times of large quantities of volcanic dust in the atmosphere. Remarkable visual effects from this dust may imply hitherto unconsidered problems in identifying alleged references to solar eclipses in African chronicles and oral traditions. Climatologist Hubert Lamb has compiled the data on volcanic eruptions and dust veils since 1500 AD and attempted to determine possible meteorological effects.

Contemporary notions of volcanic activity are predisposed to spectacular lava flows, which make more interesting journalism and greater popular interest. However, eruptions characterized by free-flowing lava –– conventionally termed Type A –– are relatively unimportant in the volcanic dust question. We are interested in so-called Type B events, usually violent explosions resulting from the inability of lava or steam to find convenient outlets. Such an explosion may inject huge quantities of dust and debris into the atmosphere, causing a wide variety of visual anomalies as they are carried around the world by high-altitude winds. If the dust veil is sufficiently dense it may even cause short-term alterations in weather patterns.

Type
Research Article
Copyright
Copyright © African Studies Association 1977

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References

Notes

1. Lamb, Hubert H., “Volcanic Dust in the Atmosphere: With a Chronology and Assessment of its Meteorological Significance,” Philosophical Transactions of the Royal Society, 266(1970), pp. 425533.Google Scholar

2. Royal Society, The Eruption of Krakatoa and Subsequent Phenomena, (London, 1888).Google Scholar The best popular account is Furneaux, Robert, Krakatoa, (Englewood Cliffs, N.J., 1964).Google Scholar

3. Lamb, , “Volcanic Dust,” pp. 431–3 (italics mine).Google Scholar

4. Ibid., pp. 463-4, 494.

5. Gray, Richard, “Eclipse Maps,” JAH, 6(1965), p. 255.CrossRefGoogle Scholar

6. Asimov, Isaac, “The Sun Vanishes,” in his Today and Tomorrow And … (New York, 1973), pp. 35–6 (italics mine).Google Scholar

7. Gray, , “Eclipse Maps,” p. 261.Google Scholar

8. Ibid., p. 259.

9. Gray, Richard, “Annular Eclipse Maps,” JAH, 9(1968), p. 149.CrossRefGoogle Scholar

10. Ibid., p. 150.

11. Gray, , “Eclipse Maps,” p. 259.Google Scholar

12. For details on calculations and measurements for dust veils see Lamb, , “Volcanic Dust,” pp. 470–6.Google Scholar

13. See tables of annual d.v.i. in Lamb, , “Volcanic Dust,” pp. 526–7.Google Scholar

14. See the historical compendium of volcanic events for the period 1500-1966 in Lamb, , “Volcanic Dust,” pp. 500–25.Google Scholar

15. Davis, Ronald W., Ethnohistorical Studies on the Kru Coast, (Newark, Del., 1976), pp. 159–76Google Scholar; Gray, , “Annular Eclipse Maps,” p. 153Google Scholar; The Times, (London), 30 August 1886, p. 6c.Google Scholar

16. Henige, David, “‘Day was of sudden turned into night:’ On the Use of Eclipses for Dating Oral History,” Comparative Studies in Society and History, 18(1976), pp. 493–5.CrossRefGoogle Scholar

17. Eddy, J.A., “The Maunder Minimum,” Science, 192(18 June 1976), pp. 11891202.CrossRefGoogle ScholarPubMed

18. Henige, , “Reflections on Early Interlacustrine Chronology: an Essay in Source Criticism,” JAR, 15(1974), p. 37Google Scholar; idem, “Eclipses,” pp. 499-500.