sea; but these changes are too insignificant to affect the destinies of
man, or the nature of the physical circumstances of things. On the
hypothesis that I have adopted, however, it must be remembered that the
present surface of the globe is merely a thin crust surrounding a nucleus
of fluid ignited matter, and consequently we can hardly be considered as
actually safe from the danger of a catastrophe by fire.

Onuphrio said: "From the view you have taken, I conclude that you
consider volcanic eruptions as owing to the central fire; indeed, their
existence offers, I think, an argument for believing that the interior of
the globe is fluid." The stranger answered: "I beg you to consider the
views I have been developing as merely hypothetical, one of the many
resting places that may be taken by the imagination in considering this
subject. There are, however, distinct facts in favour of the idea that
the interior of the globe has a higher temperature than the surface; the
heat increasing in mines the deeper we penetrate, and the number of warm
sources which rise from great depths in almost all countries, are
certainly favourable to the idea. The opinion that volcanoes are owing
to this general and simple cause is, I think, likewise more agreeable to
the analogies of things than to suppose them dependent upon partial
chemical changes, such as the action of air and water upon the
combustible bases of the earths and alkalies, though it is extremely
probable that these substances may exist beneath the surface, and may
occasion some results of volcanic fire; and on this subject my notion
may, perhaps, be more trusted, as for a long while I thought volcanic
eruptions were owing to chemical agencies of the newly discovered metals
of the earths and alkalies, and I made many, and some dangerous,
experiments in the hope of confirming this notion, but in vain."

_Amb_.--We are very much obliged to you for your geological