The oars of modern Venetian galleys were each manned by five rowers. It is impossible in this work to examine closely into all the rival theories as to what constituted a bank of oars. It seems improbable, for reasons before stated, that any vessel could have had more than five horizontal tiers. It is certain also that, in order to find room for the rowers to work above each other in these tiers, the oar-ports must have been placed, not vertically above each other, but in oblique rows, as represented in Fig. 14. It is considered by Mr. W. S. Lindsay, in his "History of Merchant Shipping and Ancient Commerce," that each of the oblique rows of oars, thus arranged, may have formed the tier referred to in the designation of the class of the vessel, for vessels larger than quinqueremes. If this were so, there would then be no difficulty in conceiving the possibility of constructing galleys with even as many as forty tiers of oars like the huge alleged galley of Ptolemy Philopater. Fig. 15 represents the disposition of the oar-ports according to this theory for an octoreme. [Illustration: FIG. 14.--Probable arrangement of oar-ports in ancient galleys.] [Illustration: FIG. 15.--Suggested arrangement of oar-ports in an octoreme.] It appears to be certain that the oars were not very advantageously arranged, or proportioned, in the old Greek galleys, or even in the Roman galleys, till the time of the early Caesars, for we read that the average speed of the Athenian triremes was 200 stadia in the day. If the stadium were equal in length to a furlong, and the working day supposed to be limited to ten hours, this would correspond to a speed of only two and a half miles an hour. The lengths of the oars in the Athenian triremes have been already given (p. 42); even those of the upper banks were extremely short--only, in fact, about a foot longer than those used in modern 8-oared racing boats. On account of their shortness and the height above the water at which they were worked, the angle which the oars made with the water was very steep and consequently disadvantageous. In the case of the Athenian triremes, this angle must have been about 23.5 deg.. This statement is confirmed by all the paintings and sculptures which have come down to us. It is proved equally by the painting of an Athenian bireme of 500 B.C. shown in Fig. 9, and by the Roman trireme, founded on the sculptures of Trajan's Column of about 110 A.D., shown in Fig. 16.[11] In fact, it is evident that the ancients, before the time of the introduction of the Liburnian galley, did not understand the art of rowing as we do to-day. The celebrated Liburnian galleys, which were first used by the Romans, for war purposes, at the battle of Actium under Augustus Caesar, were said to have had a speed of four times that of the old triremes. The modern galleys used in the Mediterranean in the seventeenth century are said to have occasionally made the passage from Naples to Palermo in seventeen hours.