[Footnote 77: M. D'Anville has given, in the Memoirs of the
Academy for the year 1756, (tom. xxx. p. 198 - 236,) a plan
of Rome on a smaller scale, but far more accurate than that
which he had delineated in 1738 for Rollin's history.
Experience had improved his knowledge and instead of Rossi's
topography, he used the new and excellent map of Nolli.
Pliny's old measure of thirteen must be reduced to eight
miles. It is easier to alter a text, than to remove hills or
buildings.
Note: Compare Gibbon, ch. xi. note 43, and xxxi. 67, and ch.
lxxi. "It is quite clear," observes Sir J. Hobhouse, "that
all these measurements differ, (in the first and second it
is 21, in the text 12 and 345 paces, in the last 10,) yet it
is equally clear that the historian avers that they are all
the same." The present extent, 12 3/4 nearly agrees with the
second statement of Gibbon. Sir. J. Hobhouse also observes
that the walls were enlarged by Constantine; but there can
be no doubt that the circuit has been much changed. Illust.
of Ch. Harold, p. 180. - M.]