As has been seen, there were, alongside of the ships of war or _naves longæ_, merchant ships or freight vessels, _naves onerariæ_. The dimensions of these latter were also rather small; as can be judged by their capacity. Their cargo, as shown by ancient documents, was stated in Greek talents or in Roman amphora (1 amphora = 26.50 m.), and later also in midimnes of Attica (1 midimne = 42.50 m.). (_Das Seewesen der Gr. mid R._, Dr. ~Em. Lübeck~, p. 22.) According to an arrangement regulating the size of merchant vessels, made in the year B. C. 218, the boats which brought goods from the senatorial possessions in Sicily and Sardinia to Rome, had a cargo space of only 786 cubic feet. It is true that descriptions of much larger vessels are found. These ships, from calculations made by Assmann and other authors, must have had a capacity of 26,000 to 200,000 cubic feet. Graser even goes so far as to say, from the quantity of freight carried, that the ship “Alexandreia” belonging to Hiero of Syracuse must have had a capacity of 240,000 cubic feet. Mention is even made of one ship having a length of 120 ells, while for another a depth of 29 ells is given. All these dimensions are not to be despised even now, but, considering the small size of the ports and navigable highways of those days as well as their lack of depth, they must have been an impossibility. Furthermore, all these numerical data rest only on hypotheses, and cannot be exact. The short, bluff merchant ship of the Ancients was certainly not longer than the vessel with oars and its average size does not seem to have exceeded that of a “tialque”. The progress of shipbuilding was gradual throughout Western Europe, and as the same may be said of the Mediterranean, since the Middle Ages, what reason is there, then, for supposing that the vessels of Antiquity were of extraordinary dimensions? In this order of ideas, the _Prora of Samothrace_, discovered in 1863 and dating from B. C. 306, gives an exact idea of the war ship of the Ancients and proves that this vessel differed little in shape and size from the ships of the Middle Ages. The bottom was slightly curved near the middle and the hull was made slender toward the ends. The mean draught of water was one metre, while that of the largest vessels scarcely exceeded 1.50 m. (~Assmann~, _Seewesen_, p. 1597, etc.) The stem and the sternpost were ornamented with signs which are unimportant for this study. Ships with oars of which the stern was rounded at the level of the water line, carried at the bow a ram, which was used to sink the enemy’s ships and to smash their oars. A heavy block of wood, ornamented with the head of a ram, prevented the ram from penetrating too far into the side of the ship which it attacked.