The Ancient Engineers, page 10
By far the greater part of the highway system was only graded, not paved. Some of the steepest slopes, however, may have been eased by cuts and fills.
We do hear of a couple of Persian engineers, or at least of Persians placed in charge of an engineering project. When Xerxes led his ill-fated expedition into Greece in —480, he decided to dig a canal through the neck of the Athos peninsula instead of sending his fleet around Mount Athos. A Persian fleet had been wrecked there by a sudden storm eleven years before during Darius' conquest of Thrace; and Xerxes was a cautious, methodical man who had been talked into this rash foray against his better judgment.
Therefore, the king placed in charge of the work two of his nobles,
Bubares and Artachaees.38 Both men were related to the royal family; Artachaees, moreover, was eight feet tall and had the loudest voice in the army. Herodotos explains how the job was done:
Now the manner in which they dug was the following: a line was drawn across by the city of Sane; and along this the various nations parceled out among themselves the work to be done. When the trench grew deep, the workmen at the bottom continued to dig, while others handled the earth, as it was dug out, to laborers placed still higher up on ladders, and these taking it, passed it still further, till it came at last to those at the top, who carried it off and emptied it away. All the other nations, therefore, except the Phoenicians, had double labor; for the sides of the trench fell in continually, as could not but happen, sinqe they made the width no greater at the top than it was required to be at the bottom. But the Phoenicians showed in this the skill which they exhibit in all their undertakings. For in the proportion of the work which was allotted to them they began by making the trench at the top twice as wide as the prescribed measure, and then as they dug downwards approached the sides nearer and nearer together, so that when they reached the bottom their part of the work was of the same width as the rest.39
Evidently the Phoenicians knew about the angle of repose of the earth of an embankment. But nobody else, including the two princely superintendents, did.
The Persian kings did not rule from any one single capital. Instead, they maintained four capitals and moved about from one to another in the course of a year. The kings and their court probably traveled about, as did medieval European kings, because the transportation of food about the empire was not yet well organized. If the king, his household troops, and his horde of nobles, officials, servants, women, and hangers-on stayed too long in any one place, they would sweep the countryside bare of edibles and cause a local famine.
Three of the four capitals were maintained in the great cities of Babylon, Susa, and Hagmatana.40 The kings also built a fourth capital, used mainly for ceremonies, at Parsa in the Persian hills of southwestern Iran. The Greeks called this place Persepolis, "Persian City." While each capital had palaces and audience halls, those at Persepolis were the most splendid.
Here Darius, his son Xerxes, and his grandson Artaxerxes41 labored for decades to make Persepolis a magnificent royal center. The buildings —palaces, audience halls, barracks, treasury, and monumental gateways and staircases—stood on a platform of scarped natural rock and limestone blocks, about 300 by 500 yards in area, which towered 40 feet above the plain and was in turn overshadowed by the Mountain of Mercy behind it.
Of the many buildings on the terrace, the two audience halls were outstanding. Both were square in plan, about 220 feet on a side, with gleaming walls of mud brick covered with gold leaf. The tiles of the roofs, plated with gold and silver, flashed dazzlingly in the clear Iranian air.
Thirty-six columns, 7 feet thick and 65 feet tall, upheld the roof of the older audience hall. These slender columns were of more delicate form than was usual at the time; they made the columns of the Hypostyle Hall of Rameses II look squat and graceless by comparison. The capitals of the Persian columns took a form peculiar to Achaemenid art. Each consisted of a pair of the forequarters of animals—bulls, lions, or composite monsters—kneeling back to back.
The later building, the Hall of a Hundred Columns, was similar, albeit the columns were smaller and more numerous. These kings put up similar buildings elsewhere. At Hagmatana, "not a single plank was left uncovered; beams and fretwork in the ceiling, and columns in the arcade and peristyle, were overlaid with plates of silver and gold, while all the tiles were of silver."42
In —331, Alexander the Great burned the buildings at royal Persepolis. Historians disagree as to whether he did this in a drunken rage, as a piece of adolescent vandalism, or as part of a deliberate policy to prove to the world the end of the Persian Empire. Some think it was an accident, but we shall never really know.
Strangely enough, this destruction helped to save some of Persepolis for us, even though Persepolis is a ruin today. The mud-brick walls have dissolved away, and earthquakes have shaken down most of the stonework. Only a few of Xerxes' graceful columns still rise against the bright blue Persian sky.
Nevertheless, much more is left of these palaces than of the royal buildings in the other three Persian capitals. After Alexander's destruction, Persepolis was deserted, since it was at best a small town in a sparsely settled, mountainous land. So the ruins remained much as Alexander left them. The other capitals, however, continued as great cities; and over the centuries the local people carried off the stones of the palaces for their own use, until today almost nothing is left of the royal edifices.
Since the Persians had never produced a class of architects, their kings called upon the subject peoples. Consequently their palaces were built in a mixed style; Scythian gryphons shared the decor with Babylonian winged bulls. It is likely that Darius and Xerxes, with their intense interest in building, kept a firm hand on the over-all designs.
An inscription of Darius at Susa tells how, in building his palace, he used cedar from Mount Lebanon, teakwood from India, stone from Elam, gold from Lydia and Bactria, and turquoise from Chorasmia.43 It also tells how he used Greek and Lydian masons, Babylonian brick makers, and Median and Egyptian goldsmiths. Each of these kings in turn maintained a studio for the Greek sculptor Telephanes, whose contemporaries ranked him among the leading artists of the time.
The long rows of reliefs on the ornamental stairways at Persepolis furnish priceless information about the costumes of the peoples of the empire. A relief of Darius giving audience, with Crown Prince Xerxes standing behind him, offers an unexpected dividend in technical knowledge. The throne whereon Darius sits is supposed to be of solid gold. But the obvious turnings of the legs and rungs of this chair show two things: first, that the lathe had been invented; and second, that the throne was really of wood with a plating of gold. Nobody ever turned a solid gold chair leg on a lathe!
Another Near Eastern people, who flourished at the time of the Assyrian, Chaldean, and Persian empires, were very active as engineers and technicians. These were the Phoenicians, who dwelt in a chain of city-states—petty kingdoms and republics—along the Lebanese coast at the eastern end of the Mediterranean. They spoke a language very similar to Hebrew, and the present-day speech of Malta is derived from this Punic tongue.
Herodotos knew what he was talking about when he spoke of "the skill which the Phoenicians exhibit in all their undertakings." They were quick to learn from others and ready to transmit their knowledge. Their engineers adopted the Assyrian methods of siege warfare. Their cities were famed for the stoutness of their fortifications. To avoid a shortage of drinking water during sieges, the island city of Arvad44 took advantage of a fresh-water spring that issued from the sea bottom near the island. The Arvadites set an inverted funnel over the spring and pumped the water to shore through a leather hose.
Phoenician shipwrights also advanced the art of shipbuilding. Egyptian ships of the early dynasties were hardly more than large canoes. When the peoples of the eastern Mediterranean began to sail the sea, they learned that rowing, with the rowers facing aft, was more efficient than paddling.
Ships split into two types: the war galley, long and narrow with many oars and a small sail; and the merchantman, short and tubby with few oars and a large sail. All ships had one single rectangular "square" sail.
The warship needed many oars to dart about in all directions during a battle. The merchantman, on the other hand, needed the space the rowers would otherwise occupy for its cargo and could not afford a large crew of rowers. Most ancient rowers, Ben-Hur to the contrary notwithstanding, were free workers, and fairly well-paid ones at that. The use of slaves and prisoners as rowers did not become common until the Renaissance.
There were also ships of an intermediate type, with more oars than a regular merchantman but fewer than a war galley. Sometimes called myoparones or "mussel-boats," they were used as naval auxiliaries, as pirate craft, and as merchantmen in pirate-infested waters. An example mentioned by Demosthenes was a twenty-oared trading ship, which plied the Black Sea.
Galleys were used for commerce only under exceptional circumstances. For example, in —VI the Carthaginians claimed a monopoly of all trade in the western Mediterranean and fed interlopers to the fish when they caught them. At this time, certain Greek traders used fifty-oared galleys to run the Carthaginian blockade. They could make a profit in spite of their horde of hungry rowers because the cargo—silver from the mines of Spanish Tartessos—was both compact and precious. Also, such a ship had a fair chance to escape when a Carthaginian galley came crawling like a colossal centipede over the horizon in pursuit.
Carthage had started as a Phoenician colony, founded (according to doubtful traditions) in —814. The Phoenicians had already sailed and rowed their little cockleshell craft the length and breadth of the Mediterranean and set up several other colonies.
During the century following the founding of Carthage, the Phoenicians developed a warship of a new and more formidable type. These may have been the ships that were taken overland in pieces and sent down the Euphrates to help King Sennacherib to put down the Babylonian rebellion. The new warship had a pointed ram at the waterline and was specially braced to withstand the shock of ramming. These ships also had a solid deck over the rowers' heads to carry fighting men.
Whereas earlier warships had but one bank of oars on each side-usually making a total of fifty oars, with one rower to each oar—the new ship had the rowers arranged in pairs on each side. They were seated in some staggered arrangement, each man of the lower bank being inboard of, aft of, or below his seat mate. The exact arrangement has been the subject of endless argument in modern times, though most authorities prefer a vertical stagger. But each rower pulled his own oar.
The new warship came to be known as a diere or bireme.45 Because it packed more muscle power per foot of length than warships of the old single-banked type, it could go faster.
About —704 a Greek shipbuilder, Ameinokles of Corinth, is said to have carried this principle a step further, by placing his oarsmen in groups of three, also staggered, though nobody knows exactly how. Each man still pulled his own oar. The resulting triere ("three-er") or trireme, driven at speeds up to seven knots46 by 170 or more rowers, became the standard battleship of the Mediterranean (—VI) and fought the great naval battles among''the Greeks, the Persians (whose navy was mainly Phoenician), and the Carthaginians.
Fig, 2. Four alternative plans suggested for the arrangement of rowers in a classical trireme (after Ucelli). The dotted figure is seated farther aft— away from the reader—than his companions. In another possible arrangement, the lowest man is seated farther inboard, so that his oar is the same length as the others.
The Phoenicians also pioneered in large-scale manufacture. Their leading products were woolen goods colored with a deep-red dye obtained from mollusks of the family Muricidae—small sea snails with spiny shells—found along the Phoenician coast. The narrow streets of
Old Tyre reeked with the stench of the dye works. The Phoenicians also turned out metal wares, which were snapped up by eager buyers in distant ports.
From Egypt, where it had long been practiced, the Phoenicians borrowed the art of making glass. The Egyptians and Mesopotamians used glass mainly for glazing beads and tiles and for making small bottles to hold cosmetics. The Phoenicians, using the excellent sand found at the mouth of the Belos River,47 developed commercial lines of bowls and other vessels. All this glass was cast, built up, or ground; glass blowing came later.
The Phoenicians and their neighbors, the Syrians and the Jews, were the first to make glass cheap enough so that ordinary folk could afford glass drinking vessels instead of cups of pottery or metal. In early Achaemenid times, glass was so precious that only the King of All Kings and his grandees could afford to drink from goblets of glass. But a few centuries later, thanks to the Syro-Phoenician glassmakers, nearly everybody could afford this luxury.
Although the Phoenicians were the leading explorers, seamen, manufacturers, and traders of their time, no people can be good at everything at once. For instance, Phoenician art is of poor quality. The Phoenicians never really tried to develop a distinctive style of their own. Instead, they mass-produced cheap copies of the art works of the Egyptians or the Greeks and peddled these gimcracks to the eager barbarians on the fringes of civilization, from Scythia to Portugal and from Senegal to Britain.
Their literature, likewise, does not seem to have amounted to much, so far as we can judge from the few scraps that have come down. Most of it seems to have perished in the destruction, one after the other, of the Phoenician cities. For Sidon was destroyed by the Persians in —345, Tyre by Alexander in —332, Carthage by the Romans in —146, and Beirut by Tryphon, the Seleucid king, in —140.48
Although the Phoenicians were not a particularly warlike people— they were businessmen, not soldiers—they defended their cities with fanatical courage and stubbornness. The Sidonians burned up themselves and their families rather than surrender to Artaxerxes. Naturally, the archives went up in smoke, too.
Other early Mediterranean peoples also accomplished notable feats of engineering before the start of written history. Even though only a few written words have come down from this age in these regions, the silent ruins bear witness to the fact that here, too, men asserted their mastery over matter with all the energy, daring, and craft of a modern engineer.
In the second millennium b.c., in Crete, a line of sea kings, ruling from Knossos, built exquisite unfortified palaces with stone walls and post-and-lintel colonnades. Pillars of tree trunks, installed upside down lest they begin to sprout during the rainy season, supported the lintels. Ceramic drain pipes carried away the water from elegant baths. The pastel murals with which the walls were decorated still show us youths and maidens performing perilous gymnastics on the horns of bulls, while long-haired Cretan men in loin cloths and ladies in off-the-bosom dresses look on.
Smaller palaces rose at Mallia on the north coast and at Phaistos on the southern. Whether these cities were parts of one realm or capitals of rival states we know not. About —1700, an earthquake shook down these palaces. Soon they rose again, more splendid than ever, and stood until the downfall of Minoan civilization about —XV. The likeliest causes for this downfall are the great eruption of the island of Thera, which blanketed the eastern Mediterranean with volcanic ash; and deforestation, which deprived the Minoans of timber for their galleys, on which their sea power depended.
Less gorgeous to look upon than the Cretan palaces but just as important from the engineering point of view was the stone-paved road that stretched away from Knossos and possibly linked all three capitals. This was the first stone-paved road in the European area and perhaps one of the first in the world.
During and after the great days of Crete, kings on the Greek mainland built palaces at Mycenae and Tiryns, fortified with thick cyclopean walls. From a distance these structures look not unlike ruined medieval castles. Up close, you see the crude strength of the massive masonry, of enormous stones with smaller stones plugging the chinks between them, and realize that here are relics of an earlier, simpler, and ruder world.
The Mycenaean kings also built remarkable beehive tombs for departed royalty. These tombs had the form of huge corbelled domes, which, when finished, were completely buried under tons of earth, making artificial hills. Buried with the dead were quantities of jewelry and masks of thin hammered gold.
During the same period, the people of Sardinia built no less than 6,500 thick-walled defensive structures, from single towers to complete castles, using the same cyclopean construction. Interior rooms and passages were corbelled, so that the rooms had a tall conical shape. The prehistoric Maltese, using similar methods, raised nearly a score of huge stone temples.
So, as far as engineering is concerned, the Golden Age of Greece was a natural outgrowth of the technical methods already worked out by various Mediterranean peoples in the days before written history. While mighty monolithic empires rose and fell in the river valleys of the East, the Mediterranean folk—lively, garrulous, enterprising, and often irreverent—grew swiftly in technical skills, until they bade fair to overtake the older cultures of the lands of morning.
FOUR
THE GREEK
ENGINEERS
Around —1000, when David and Solomon reigned in Israel, the young Mediterranean civilization of Crete and Mycenae sank under the invasion of the Dorians and other barbarous newcomers. Three to four centuries later, the invaders had mingled with the natives of the rocky isles and rugged shores of the Aegean Sea to form a new folk, the Hellenes or Greeks. The Greeks dimly remembered the cultured era before the invasions in legends like those of the siege of Troy, the wanderings of Odysseus, and the reign of King Minos in Crete. No true, trustworthy history, however, survived from that elder day, because no writings that anybody could read came down.
