On the site of the ancient city of the Aurunci, and on the volcanic phenomena which it exhibits / [Charles Daubeny].

  • Charles Daubeny
Date:
1846
Catalogue details

Licence: Public Domain Mark

Credit: On the site of the ancient city of the Aurunci, and on the volcanic phenomena which it exhibits / [Charles Daubeny]. Source: Wellcome Collection.

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    modern lavas, whilst they abound amongst the ejected masses imbedded in the tuff of Monte Somma. Having now endeavoured to trace the particulars in which the processes of an igneous character going on at the present day differ from those which gave rise to the rocks commonly called plutonic, I will next briefly consider, which of the commonly received theories of volcanos is most reconcilable with the phenomena which have just been pointed out. I may remark in the first place, that there are only two modes of explaining volcanic action, which deserve a moment’s attention, when viewed by the lights of modern science. One set of philosophers, inferring from the oblate spheroidal figure of the globe, that it was once in a state of fluidity from igneous fusion, and again, presuming, from the increasing temperature ob¬ served as we descend deeper and deeper into its recesses, that it may retain enough of its heat at the ])resent time to be preserved in a state of fusion below certain depths, propose a very simple mode of explaining the evolution of melted matter from volcanos, by attributing it to the contraction of the crust of the globe upon its fluid contents, by which a portion of the latter is from time to time expressed at the ])oints of least resistance. Others, considering—that all the matters ejected from a volcano contain an inflammable base united with oxygen—that the latter need not be supposed to have been j)resent in the interior of the earth
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