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Darwin Correspondence Project

To Charles Lyell   24 March [1853]

Down Farnborough Kent

March 24th.

My dear Lyell

I have often puzzled over Dana’s case, in itself, & in relation to the trains of S. American volcanos, of different heights, in action at the same time (p. 605, vol. V. Geolog Transact)1 I can throw no light on the subject.— I presume you remember that Hopkins in some one, (I forget which) of his papers,2 discusses such cases, & urgently wishes the height of the fluid lava was known in adjoining volcanos when in contemporaneous action: he argues vehemently against (as far as I remember) volcanos in action of different heights being connected with one common source of liquefied rock. If lava was as fluid as water, the case would indeed be hopeless; & I fancy we shd. be led to look at the deep-seated rock as solid, though intensely hot, & becoming fluid, as soon as a crack lessened the tension of the superincumbent strata. But don’t you think that viscid lava might be very slow in communicating its pressure equally in all directions? I remember thinking strongly that Dana’s case within the one crater of Kilaulea, proved too much: it really seems monstrous to suppose that the lava within the same crater is not connected at no very great depth.

When one reflects on (& still better sees) the enormous masses of lava apparently shot miles high up, like cannon balls, the force seems out of all proportion to the mere gravity of the liquefied lava;3 I should think that a channel a little straighter or more open wd. determine the line of explosion, like the mouth of a cannon compared to the touch-hole. If a high-pressure Boiler was cracked across, no one wd. think for a moment that the quantity of water & steam expelled at different points, depended on the less or greater height of the water within the boiler above these points, but on the size of the crack at these points: And steam & water might be driven out both at top & bottom. May not a volcano be likened to a protruding & cracked portion on a vast natural high-pressure Boiler, formed by the surrounding area of country? In fact, I think my simile would be truer, if the difference consisted only in the cracked case of the Boiler being much thicker in some parts than in others, & therefore having to expel a greater thickness or depth of water in the thicker cracks or parts,—a difference of course absolutely as nothing— I have seen an old Boiler in action with steam & drops of water spurting out of some of the rivet-holes: no one would think whether the rivet holes passed through a greater or less thickness of iron; or were connected with the water higher or lower within the Boiler, so small would the gravity be compared with the force of the steam. If the Boiler had been not heated, then of course there wd. be a great difference, whether the rivet holes entered the water high or low, so that there was greater or less pressure of gravity. How to close my volcanic rivet-holes I don’t know! I do not know whether you will understand what I am driving at; & it will not signify much whether you do or not.—4

I remember in old days (I may mention the subject, as we are on it) often wishing I could get you to look at continental elevations as the phenomenon, & volcanic outbursts & tilting up of mountain chains as connected, but quite secondary phenomena: I became deeply impressed with the truth of this view in S. America, & I do not think that you hold it or if so, make it clear: the same explanation, whatever it may be, which will account for the whole coast of Chile rising, will & must apply to the volcanic action in the Cordillera, though modified no doubt by the liquefied rock coming to the surface & reaching water & so rendered explosive. To me it appears that this ought to be borne in mind in your present subject of discussion.—5

I have written at too great length; I have amused myself, if I have done you no good: so farewell | My dear Lyell | Ever yours very truly | C. Darwin

N.B. You finish by saying “I sent you a letter yesterday”. I am very sorry to say that not one arrived; No Letter I shall be up for the next Geolog. meeting.6

Footnotes

In his paper ‘On the connexion of certain volcanic phenomena in South America’ (read 7 March 1838), published in the fifth volume of the Transactions of the Geological Society of London, CD had argued that the elevation of the land and volcanic activity were connected and that when elevation occurred there was an unusual degree of activity in trains of neighbouring volcanoes (Collected papers 1: 53–86). Dana’s ‘case’ was put forward in Dana 1852, pp. 254–5, where he stated that when Mauna Loa erupted it was not accompanied by an earthquake and there was no sympathetic eruption from Kilauea, a crater on the flanks of Mauna Loa. After studying the shifts in levels of the crater floor and the level of lava in Kilauea in connection with the frequency of its eruptions, Dana concluded: ‘With such facts, in connection with others … we are assuredly sustained in not admitting the universal application of the so-called elevation theory.’ (Dana 1852, p. 257).
Dana considered ‘that the hydrostatic pressure of the central column of lavas in the mountain was the power that kept the jet in action. Such a fountain of molten rock is majestic beyond conception; and the more wonderful, the more majestic, viewed as the effect of simple pressure, with none of the convulsive heavings common in other volcanoes.’ (Dana 1852, pp. 254–5).
Lyell was at work on the ninth edition of his Principles of geology, published June 1853, in which he introduced a discussion of Dana’s ‘case’ (see n. 1, above) and concluded (C. Lyell 1853b, p. 553): Without pretending to solve this enigma, I cannot refrain from remarking, that the supposed independence of several orifices of eruption in one crater like Kilauea, when adduced in confirmation of the doctrine of two distinct sources of volcanic action underneath one mountain, proves too much. No one can doubt, that the pools of lava in Kilauea have been derived from some common reservoir, and have resulted from a combination of causes commonly called volcanic, which are at work in the interior at some unknown distance below. These causes have given rise in Mount Loa to eruptions from many points, but principally from one centre, so that a vast dome of ejected matter has been piled up. The subsidiary crater has evidently never given much relief to the imprisoned, heated, and liquefied matter, for Kilauea does not form a lateral protuberance interfering with the general shape or uniform outline of Mount Loa.
Lyell referred to CD’s article ‘On the connexion of certain volcanic phenomena in South America’ in C. Lyell 1853b and, after mentioning the permanent upheaval of land after earthquakes in Chile, stated: ‘it will also be seen that great shocks often coincide with eruptions, either submarine, or from the cones of the Andes, showing the identity of the force which elevates continents with that which causes volcanic outbursts.’ (p. 347).
The Geological Society met on 6 April 1853. CD’s Health diary (Down House MS) indicates that CD stayed in London from 4 to 7 April.

Bibliography

Collected papers: The collected papers of Charles Darwin. Edited by Paul H. Barrett. 2 vols. Chicago and London: University of Chicago Press. 1977.

Hopkins, William. 1847. Report on the geological theories of elevation and earthquakes. Report of the 17th meeting of the British Association for the Advancement of Science held and Oxford, pp. 33-92. [vols. 5,6,8]

Summary

Volcanic activity of Mt Kilauea as described by Dana [Am. J. Sci. 2d ser. 9 (1850): 347–64]. Discusses the mechanics of volcanic eruption. Disputes view of William Hopkins that simultaneous action by volcanoes of different heights must come from separate lava sources. Notes relationship of continental elevation to volcanic action.

Letter details

Letter no.
DCP-LETT-1508
From
Charles Robert Darwin
To
Charles Lyell, 1st baronet
Sent from
Down
Source of text
American Philosophical Society (Mss.B.D25.105)
Physical description
5pp

Please cite as

Darwin Correspondence Project, “Letter no. 1508,” accessed on 12 December 2019, https://www.darwinproject.ac.uk/letter/DCP-LETT-1508.xml

Also published in The Correspondence of Charles Darwin, vol. 5

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