Page:General History of Europe 1921.djvu/108

64 General History of Europe bought slaves, if he could afford it, and trained them to carry on the manufacturing. The slaves were commonly the inhabitants of towns that had been conquered in the wars that went on con- stantly. The former little shops in this way grew into factories with a score of hands. Henceforth slave labor became and con- tinued an important element in Greek life. In Athens, especially, the factories grew to a size hitherto un- known in the Greek world and filled a large district of the city. Beautiful vases were made, which were often placed in the tombs of the dead. They are found by modern excavators in places as far from each other as the interior of Asia Minor, the Nile delta, and central Italy. Ships had to be made larger and, in addition to oars, sails invented long before by the Egyptians were used. The new vessels were so heavy that they could no longer be drawn up on the shore, so that harbors had to be built for them. The protection of these merchant ships demanded more effective warships, and the distinction gradually arose between a " man-of- war," or battleship, and a "merchantman." Warships must be independent of the wind, and hence they were still driven by oars. The oarsmen were now arranged in three rows, and the power of an old "fifty-oar" was thus multiplied by three without essen- tially increasing the ship's size. Battleships having the oars in three rows were called "triremes." These improvements were widely used by 500 B.C. 93. Adoption of Coinage by the Greeks (Early Seventh Century B.C.). Meantime Greek business life had entered upon a new epoch, due to the introduction of coined money. Not long after 700 B. c. the kings of Lydia in Asia Minor, following oriental custom, cut up silver into lumps of a fixed weight. These they began to stamp with some symbol of the king or State, to show that the State guaranteed their value. These pieces formed the earliest-known coins (see accompanying illustration). This great convenience was quickly adopted by the Greeks. The Athenians began to use as their commonest coin a bit of silver weighing the hundredth part of a Babylonian mina (our