ents the appearance of a blackened mass.
Of the road itself we shall speak hereafter at some length in connection
with Trajan's expedition, but a few words concerning his bridge at
Turnu-Severin may still be added. All that remains visible to the
traveller to-day are the two terminal piers, of which sketches are here
given; but between those piers the bridge spanned the river, and a very
low state of the water discloses the tops of several other piers still
standing. In speaking of one bridge we have taken rather a liberty with
the facts, for it is now pretty generally admitted that there were
really two structures. Further down the river is a small island which,
in former times, is said to have extended to where the remains of the
bridge are found, and upon this tongue of land the ends of the sections
starting from either shore rested. The land is supposed either to have
sunk or to have been washed away by the current.[22] The bridge, to
which further reference will be made in our historical sketch, was built
after the plans of Apollodorus, the architect of Trajan's Column at
Rome. It was commenced about 103 A.D., and probably consisted of twenty
piers, each 150 Roman feet high and 60 feet broad, and the distance
between the two terminal piers on the banks is about 3,900 English feet.
The piers were of stone, but the upper part of the bridge was wood. In
the northern pier the stone consists of rubble, or artificial
conglomerate composed of small roundish stones and cement, and this was
probably cast into blocks, but the one on the right (southern) bank is
of hewn stone. On the northern side there is an old wall running up
from the pier to the ruins of a tower which was evidently connected with
the bridge.

[Illustration: TERMINAL PIER ON SERVIAN SIDE. (FROM A SKETCH BY THE
AUTHOR.)]

But it would be better that we should reserve any further remarks
concerning the archaeological relics of Roumania, and also some
observations of immediate interest in connection with the Danube, until
we have completed a brief account of the water system of the country.

Between the 'Iron Gates' and its three embouchures, namely, the Khilia,
Sulina, and St. George's mouths, of which only the second is navigable
by large vessels, the Danube stretches fora distance of about 650
miles,[23] and receives in its course numerous tributaries, whereof the
following are the principal on the Roumanian side. The Pruth is the most
important. It for