260 
OBSERVATIONS ON THE PERIPLUS. 
The position of Berenice has been laid down from local circum- 
stances with as much certainty as that of Aduli. It is described by 
Strabo as situated in the bottom of a bay, which, on account of its 
numerous shoals and rocks, had been designated azdQotpTog, immun- 
dus, and, as being at the extremity of the Thebais or Upper Egypt. 
The latter observation limits our conjectures to within 23° 30' and 
24°, and the former fixes us in the bottom of a bay which has pre- 
served its name, and among modern navigators is called Foul Bay, 
According to D'Anville this is in 23° 15'. 
--^ Gosselin - - 23° 2S'. 
— an English chart 23° 19'. 
Though the distances in the Periplus deserve a greater degree of 
credit than usual from their being given in words at full length, 
instead of figures, yet I cannot receive them without some degree 
of caution, from their being evidently given in round numbers, 
without any fractional parts, and from a knowledge of the difficulty 
of measuring distances at sea, without a nicer degree of observation 
than was probably employed by Egyptian merchants, or is now 
used by those of our own nation. 
I should therefore consider the relative distances between Aduli, 
Berenice, and Ptolemais Theron, as a more certain guide to the 
discovery of the latter. The whole distance is five hundred and 
seventy-nine miles, three sevenths of which, or two hundred forty- 
six miles, if measured from Aduli on the chart, will exactly reach 
a peninsula in latitude 18° ^4', of which I shall hereafter have oc* 
casion to speak, and where the more valuable data of local circum- 
stances seem to point out the Ptolemais Theron of the Periplus. 
I am well aware that it is impossible to reconcile this conclusion 
