ied by the Appian aqueduct. It
was determined, therefore, to bring water from a greater height, and from
a greater distance, and the river Anio, above the falls at Tivoli, was
selected for this purpose. The second aqueduct, the Anio Vetus, was no
less than 42 miles in length, and was, like the Appian, entirely under
the surface of the ground, except at its entrance into Rome at a point
about 60 ft. higher than the level of the Appian aqueduct.

Little search has been made for the remains of this aqueduct, and its
exact course is not known; but during my examination of the remains of
the subsequent aqueducts at a place called the Porta Furba, near Rome,
where the ruins of five aqueducts are seen together, and at, or close to,
which point the Anio Vetus must also have passed underground, I was
rewarded for my search by discovering a hole, something like a fox's
hole, leading into the ground; and on clearing away a few loose stones
which had apparently been thrown into it, and putting my arm in, I found
that it led into the specus or channel of an underground aqueduct; and on
relating this incident to the late Mr. John Henry Parker, the
antiquarian, who was then in Rome, and showing him a sketch of the place,
he said that he had no doubt that I had been fortunate enough to discover
the exact position of the veritable Anio Vetus at that spot. These two
aqueducts sufficed for the supply of Rome with water for about 120 years,
for Frontinus tells us that 127 years after the date at which the
construction of the Anio Vetus was undertaken--that is to say, the 608th
year after the foundation of the city--the increase of the city
necessitated a more ample supply of water, and it was determined to bring
it from a still greater distance. It was no longer considered necessary
to conceal the aqueduct underground during the whole of its course, and
so it was in part carried above ground on embankments or supported upon
arches of masonry. The water was brought from some pools in one of the
valleys on the eastern side of the Anio, some miles farther up than the
point from which the Anio Vetus was supplied; and the new aqueduct, which
was 54 miles in length, was called the Marcian, after the Praetor Marcius,
to whom the work was intrusted. Frontinus also tells us the history of
the other six aqueducts which were in existence in his time, viz., the
Tepulan, the Julian, the Virgo, the Alsietine or Augustan, the Claudian,
and the Anio Novus;