Sixthly, and lastly, the ships of the Phæacians perform their voyages by an inward instinct, and with a rapidity described as marvellous. ~_Evidence as to rates of motion._~ The language of the poems nowhere takes cognizance of any difference in speed as between sailing and rowing. For example, when Achilles speaks of the time of his voyage to Phthia as dependent upon εὐπλοίη, which the favour of Neptune could give, he evidently means a good sea and the absence of tempest, and does not at all bargain for a wind from a particular quarter, which was not a matter lying within Neptune’s especial province. Nor does there seem to be, on general grounds, any cause for assuming a difference between the average speeds of rowing and of sailing, when we consider, in favour of the first, that the crew rowed almost to a man, with little cargo to carry; and, to the prejudice of the second, that the science and art of building quick sailers could not then have been understood. I therefore take rowing and sailing as equal in celerity. So that we have in reality no more than five different cases to consider. But, again, I think there is no reason why we should assume a difference in speed between drifting on a piece of timber, and making way by floating and swimming only. In practicability there may be a considerable difference: but that is not the point before us. The four methods now remaining seem to require the assumption of different speeds respectively. Now Homer has supplied us with the times necessary for performing known distances in two cases; and has also given us a third case, which may be used for checking one of the other instances. A case of known distance is that from the mouth of the Straits of Gallipoli to Phthia. This, according to Achilles in the Ninth Iliad[570], would, with favourable weather, be performed so as to arrive on the third day. It may amount to a little more than three degrees, and may be taken at two hundred and twenty miles. The time is three days and two nights. So that, for ordinary sailing or rowing, a day and a night may be taken at about ninety miles, of course without any pretension to minute accuracy. [570] Il. ix. 362. Secondly. With a good passage, a ship sailing from Crete to Egypt arrives on the fifth day (Od. xiv. 257). But we cannot consider Homer’s opinion of the distance between Crete and Egypt as entitled to the full weight of his experimental knowledge. Again, it is to be borne in mind, that here the north wind, which carries the ship, was a prime one (ἀκραὴς καλὸς, 253). Lastly, much might depend on the part of Crete, from which we suppose the vessel to have sailed. As respects the last-named question, we must, from the habits of ancient navigation, suppose the eastern extremity of the island to have been the point of departure; because no sailor would have committed himself to Boreas on the open sea, as long as he could make way under cover of a shore lying to windward.