Note 764 — BOOK VI. AN ACCOUNT OF COUNTRIES, NATIONS, SEAS, TOWNS, HAVENS, MOUNTAINS, RIVERS, DISTANCES, AND PEOPLES WHO NOW EXIST, OR FORMERLY EXISTED. (continued 2)
John Bostock translation
It is impossible to see clearly what he means. Littré says that it has been explained by some to mean, that from the Purpurariæ, or Madeira Islands, it is a course of 250 miles to the west to the Fortunatæ or Canary Islands; but that to return from the Fortunatæ to the Purpurariæ, required a more circuitous route in an easterly direction.