said the stranger, "is what I believe to be the source of those large and
durable stones which you see in the plain before you. This water rapidly
deposits calcareous matter, and even if you throw a stick into it, a few
hours is sufficient to give it a coating of this substance. Whichever
way you turn your eyes you see masses of this recently-produced marble,
the consequence of the overflowing of the lake during the winter floods,
and in that large excavation where you saw the buffaloes disappear you
may observe that immense masses have been removed, as if by the hand of
art and in remote times. The marble that remains in the quarry is of the
same texture and character as that which you see in the ruins of Paestum,
and I think it is scarcely possible to doubt that the builders of those
extraordinary structures derived a part of their materials from this
spot." Ambrosio gave his assent to this opinion of the stranger; and I
took the liberty of asking him as to the quantity of calcareous matter
contained in solution in the lake, saying that it appeared to me, for so
rapid and considerable an effect of deposition, there must be an unusual
quantity of solid matter dissolved by the water or some peculiar
circumstance of solution. The stranger replied, "This water is like
many, I may say most of the sources which rise at the foot of the
Apennines: it holds carbonic acid in solution which has dissolved a
portion of the calcareous matter of the rock through which it has passed.
This carbonic acid is dissipated in the atmosphere, and the marble,
slowly thrown down, assumes a crystalline form and produces coherent
stones. The lake before us is not particularly rich in the quantity of
calcareous matter that it contains, for, as I have found by experience, a
pint of it does not afford more than five or six grains; but the quantity
of fluid and the length of time are sufficient to account for the immense
quantities of tufa and rock which in the course of ages have accumulated
in this situation." Onuphrio's curiosity was excited by this statement
of the stranger, and he said, "May I take the liberty of asking if you