e northwest to Rome, and
thence to Jerusalem, a southeastern point of the empire. There were
several thousand miles of road in Italy alone. Rome's highways were
constructed for the purpose of facilitating military movements, but the
benefits which commerce derived from them cannot easily be
overestimated. These military roads were usually laid out in straight
lines from one station to another. Natural obstacles were frequently
passed by means of very extensive works, as excavations, bridges, and,
in some instances, long tunnels. The resources of the Roman Empire were
almost inexhaustible, and no public expenditures were larger than those
made on account of the construction of new roads. The fact that many of
these roads have borne the traffic of almost two thousand years without
material injury is abundant proof of the unsurpassed solidity of their
construction. The Roman engineers always secured a firm bottom, which
was done, when necessary, by ramming the ground with small stones, or
fragments of brick. Upon this foundation was placed a pavement of large
stones, which were firmly set in cement. These stones were sometimes
square, but more frequently irregular. They were, however, always
accurately fitted to each other. Many varieties of stone were used, but
the preference was given to basalt. Where large blocks could not be
conveniently obtained, small stones of hard quality were sometimes
cemented together with lime, forming a kind of concrete, of which masses
extending to a depth of several feet are still in existence. The
strength of the pavements is illustrated by the fact that the substrata
of some have been so completely washed away by water, without disturbing
the surface, that a man may creep under the road from side to side while
carriages pass over the pavement as over a bridge. The roads were
generally raised above the ordinary surface of the ground. They
frequently had two wagon-tracks, which were separated by a raised
foot-path in the center, and blocks of stone at intervals, to enable
travelers to mount on horseback. Furthermore, each mile was marked by a
numbered post, the distance being counted from the gate of the wall of
Servius. The mile-post was at first a roughly hewn stone, which in time
was exchanged for a monument, especially in the vicinity of Rome and
other large cities. The most celebrated road of Italy, which has always
excited the admiration of the student of antiquity, was the Via Appia,
t