of Caesar v.

2) or 40 miles (=320 stadia, according to Strabo iv.

5, 2, who doubtless drew his account from Caesar).

From Caesar's words (iv.

21) that he had chosen "the shortest crossing," we may doubtless reasonably infer that he crossed not the Channel but the Straits of Calais, but by no means that he crossed the latter by the mathematically shortest line.