actual circumference of the gulf of the Greater Syrtis may be estimated
at four hundred and twenty-two geographic miles, and its
diameter at two hundred and forty-six*: so that it would be
necessary to alter both the circumference and diameter given by
Strabo before any use could be made of his dimensions; and then
the measurements must be taken on the authority of the commentators,
since they would be no longer those of the geographer. In
' short, the difficulty appears to be scarcely surmountable ; for though
it is evident that the passage is not as Strabo left it, we have no sufficient
data for deciding what it really was originally f. The measurements
given by Pliny are somewhat nearer the truth %; indeed his
diameter of the gulf may be considered as remarkably accurate; for
it is stated at three hundred and thirteen Roman miles, equal to two
hundred and forty-eight and a quarter geographic miles, and there
is consequently no more than two miles and a quarter difference
between these dimensions and the actual diameter. His circumference,
however, is not by any means so accurate; it is given at six
* This estimate of the circumference is deduced from the camel-track, corrected by
observations; and the accuracy to which this mode of computation maybe brought
by care and attention, and by making the proper allowances, will be seen in the examples
which we shall hereafter submit of it.
t If, however, we take the measurements just quoted from the second book of Strabo,
as those which he intended to be received in the present case, we .shall find that the
428TV?y miles, resulting from the 5000 stadia of Eratosthenes, come very near the truth.
The other measurements, however, are far from correct. I t will be observed that the
diameter given in this place is the same with that mentioned in the second book (1500
stadia).
+ Inde Syrtis Major, circuitu DCXXV. aditu autem, CCCXIII. M. Passuum.—Nat.
Hist. lib. v. cap. 4.
hundred and twenty-five Roman miles, which are equal to four hundred
and ninety-four geographic miles, and will therefore leave a
difference of seventy-two geographic miles between this measurement
of the circuit and thè actual one. The difference also exists on the
wrong side ; that is to say, the whole distance of Pliny is not only
much more than the actual distance by observations, but much
more than the actual road-distance, which is the longest which can
be allowed. The diameter of the gulf, already stated, of this author,
will be found to coincide remarkably well with the measurement
which may be deduced from the distance he has given us in another
place, between the cities of Leptis Magna and Berenice, of three
hundred and eighty-five Roman miles * : for the distance between
Lebida (Leptis Magna) and Mesurata, the western extremity of the
gulf, may be reckoned at fifty-eight geographic miles, equal to
seventy-three Roman miles ; so that this being deducted from the
whole distance given, of three hundred and eighty-five M.P. we shall
have a remainder of three hundred and twelve of the same for
the distance between Mesurata and Bengazi, leaving a difference of
only one mile between the diameter of the gulf thus deduced and
that above stated of three hundred and thirteen. But although we
may infer, from the coincidence of the two measurements, that the
three hundred and twelve miles in question may be taken as distance
across the gulf, they are by no means stated to be such in the text ;
and if they had chanced to coincide with the circumference instead
* Nec procul ante Oppidum, (Berenice) fluvius Letbon, lucus sacer, ubi Hesperidum
horti memorantur. Abest a Lepti CCCLXXXV. M. P. (Lib. v. cap. 5.)