256 
JOURNEY FROM 
actual circumference of the gulf of the Greater Syrtis may be esti- 
mated 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 commen- 
tators, 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 suffi- 
cient data for deciding what it really was originally -j-. The measure- 
ments 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 Koman 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 circumfer- 
ence, however, is not by any means so accurate ; it is given at six 
* This estimate of the ciixumference is deduced from the camel-track, corrected by 
observations ; and the accuracy to which this mode of computation may be brought 
by care and attention, and by making the proper allowances, will be seen in the exam- 
ples 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 
428^0*0 miles, resulting from the 5000 stadia of Eratosthenes, come very near the truth. 
The other measurements, however, are far from correct. It will be observed that the 
diameter given in this place is the same with that mentioned in the second book (1500 
stadia). 
I Inde Syrtis Major, circuitu DCXXV. aditu autem, CCCXIII, M. Passuum. — Nat. 
Hist. lib. V. cap. 4. 
