no doubt contains the same kinds of floating islands,
the same plants, and the same insects. During the fifteen years that I
have known it it has appeared precisely identical in these respects, and
yet it has the character of an accidental phenomenon depending upon
subterraneous fire. How marvellous then are those laws by which even the
humblest types of organic existence are preserved though born amidst the
sources of their destruction, and by which a species of immortality is
given to generations floating, as it were, like evanescent bubbles, on a
stream raised from the deepest caverns of the earth, and instantly losing
what may be called its spirit in the atmosphere." These last
observations of the stranger recalled to my recollection some phenomena
which I had observed many years ago, and of which I could then give no
satisfactory explanation. I was shooting in the marshes which surround
the ruins of Gabia, and where there are still remains supposed to be of
the Alexandrine aqueduct; I observed a small insulated hill, apparently
entirely composed of travertine, and from its summit there were
formations of tufa which had evidently been produced by running water,
but the whole mass was now perfectly dry and encrusted by vegetables. At
first I suspected that this little mountain had been formed by a jet of
calcareous water, a kind of small fountain analogous to the Geiser, which
had deposited travertine and continued to rise through the basin flowing
from a higher level; but the irregular form of the eminence did not
correspond to this idea, and I remained perplexed with the fact and
unable to satisfy myself as to its cause. The views of the stranger
appeared to me now to make it probable that the calcareous water had
issued from ancient leaks in the aqueduct and formed a hillock that had
encased the bricks of the erection, which in other parts, where not
encrusted by travertine, had become entirely decayed, degraded, and
removed from the soil. I mentioned the circumstance and my suspicion of
its nature. The stranger said: "You are perfectly correct in your idea.
I know the spot well, and if you had not mentioned it I should probably
have quoted it as an instance in which the works of art are preserved, as
it were, by the accidents of Nature. I was so struck by this appearance
last year that I had the travertine partially removed by some workmen,
and I found beneath it the canal of the aqueduct in a perfect stat