Strabo Geography 2.4.5

[5] Again, however, Polybius makes an incorrect assertion, in stating that the whole length of Europe is unequal to that of Africa and Asia taken together. He tells us “that the entrance at the Pillars corresponds in direction to the equinoctial west, and that the Don flows from the summer rising, ¹ consequently the length of Europe is less than that of Asia and Africa taken together by the space between the summer rising and the equinoctial rising, ² since Asia occupies the eastern portion of the northern semicircle. Now, in addition to the obscurity which Polybius throws over subjects which might have been simply stated, it is false that the river Don flows from the summer rising. For all who are acquainted with these localities inform us that this river flows from the north into the Maeotis, so that the mouth of the river lies under the same meridian as that of the Maeotis; and so in fact does the whole river as far as is known. ³