138 SECTIONAL ADDRESSES. 
Tiber water with them on all their journeys (the former had it sent as 
far as Marseilles), which shows that they must have been proof against 
typhoid ?* 
In the time of the Republic the drainage system was under the general 
control of the censors, who let out contracts for the necessary constructions 
or repairs in this as in other classes of public works. They also had charge 
of the river banks and channel, and in 54 B.c. they erected a series of 
boundary stones (cippz) along both banks to prevent encroachment by 
private persons. Under Augustus in 8 B.c. the consuls of the year erected 
another series of terminal stones, and Augustus himself a third in 7-6 B.c. 
Tiberius, after a great inundation of the Tiber in the second year of 
his reign (A.D. 15), instituted for the first time a special board of five 
curatores riparum et alver Tiberis, who probably looked after the sewers 
as well; though until the time of Trajan the charge of the sewerage does 
not actually appear in the formal title of the curator—for from the time of 
Vespasian onwards only one is mentioned, who was either the president of 
the board or a single official who had taken its place. The last inscriptions 
we have belong to the time of Diocletian. In the series of cippz which we 
owe to Augustus himself in 7-6 B.c. we find upon each stone, for the first 
time, the distances to the next one given, from the front, the back, the 
right or the left, as the case may be. We thus see that the boundary 
followed a zigzag line along the bank. The czppi have been found along 
both banks from the Pons Mulvius (the modern Ponte Molle) of the Via 
Flaminia, two miles above the city, down to a point opposite 8. Paolo ; 
but recently two of those of the curatores of the time of Tiberius were 
found at Ostia, on the ancient right bank of the river, which has completely 
changed its course owing to the great flood of 1557, so that we must 
assume that their authority extended right down to the mouth of the river 
—how far up we cannot say. 
But besides the erection of boundary stones, a good deal was done in 
the way of actual regulation of the river bank. There was no continuous 
embankment wall, as at present, but walls seem to have been built at the 
points where they were most needed. The modern engineers attempted 
to impose a uniform width of 100 metres on a river, the volume of which is 
liable to variations so great as that which the Tiber undergoes. This 
has led to the formation of sandbanks in places where the new bed, often 
double the width of the old, is too large for the ordinary state of the river ; 
while the attempt to force the river into a less tortuous course above the 
island, and the widening of the right branch of it from 48 to 75 metres led 
to the silting up of the left-hand branch, except in times of flood. As a 
result, the river was driven against the right-hand embankment, the 
foundations of which were not protected by aprons, and consequently 
a length of 125 yards of the wall collapsed into the river in the flood of 
December 1900. Measures have now been taken to diminish the amount 
of water passing through the right-hand channel and to keep the left- 
hand channel open, and have met with a certain measure of success. 
The Romans, at one point at any rate, at the Pons Aelius built by the 
Emperor Hadrian (the modern Ponte S. Angelo), were wise enough to 
provide three different widths of channel for different seasons of the year, 
in correspondence with which the bridge was provided with extra flood 
5 Modio, Il Tevere, p. 8 v. 
