106. The Evolution of the Trireme.—The genesis of the trireme was the old _penteconter_ (“fifty-oar ship”) which, in its prime features, was simply a long, narrow, open hull, with slightly raised prow and stern cabins, pulling twenty-five oars to a side. There are a few penteconters still in existence, though the great naval powers have long since scorned them. It was a good while before the battle of Salamis that the Greek sea warriors began to feel the need of larger warships. It was impossible to continue the simple scheme of the penteconter. To get more oars all on one tier you must make a longer boat, but you could not increase the beam, for, if you did, the whole craft would get so heavy that it would not row rapidly; and the penteconter was already so long in relation to its beam as to be somewhat unsafe. A device was needed to get more oars into the water without increasing the length over much. The result was the _bireme_ (two-banker) which was speedily replaced by the still more efficient _trireme_ (three-banker), the standard battleship of all the Greek navies.[*] [*] By the end of the fourth century B.C., vessels with four and five banks of oars (quadriremes and quinqueremes) had become the regular fighting ships, but they differed probably only in size, not in principle, from the trireme. [Illustration: AN ATHENIAN TRIREME The scheme for the sails is conjectural, and no attempt is made to show the exact number of oars.] 107. The Hull of a Trireme.—The _Invincible_ has a hull of fir strengthened by a solid oak keel, very essential if she is to be hauled up frequently. Her hull is painted black, but there is abundance of scarlet, bright blue, and gilding upon her prow, stern, and upper works. The slim hull itself is about 140 feet long, 14 feet wide, and rides the harbor so lightly as to show it draws very little water; for the warship, even more perhaps than the merchantman, is built on the theory that her crew must drag her up upon the beach almost every night. While we study the vessel we are soon told that, although triremes have been in general use since, say, 500 B.C., nevertheless the ships that fought at Salamis were decidedly simpler affairs than those of three generations later. In those old “aphract” vessels the upper tier of rowers had to sit exposed on their benches with no real protection from the enemy’s darts; but in the new “cataphract” ships like the _Invincible_ there is a stout solid bulwark built up to shield the oarsmen from hostile sight and missiles alike. All this makes the ships of Demosthene’s day much handsomer, taller affairs than their predecessors which Themistocles commanded; nevertheless the old and the new triremes have most essentials in common. The day is far off when a battleship twenty years old will be called “hopelessly obsolete” by the naval critics.[*]