You Could Look It Up (10 page)

Even after alphabetical order was familiar, many reference books were arranged topically or thematically, using the alphabet only within sections—so an encyclopedia's section on trees might put
ash
before
beech
, but the trees were kept together. Only in the seventeenth and eighteenth century did people realize how difficult it was to come up with a taxonomy of knowledge more intuitive than the alphabet. Alphabetical order still had enemies, who hated the thought of subjecting all human knowledge—a field that was supposed to be rationally structured—to the tyranny of an arbitrary order. It felt like failure. As the historian Peter Burke says, complete alphabetization “appears to have been adopted, originally at least, out of a sense of defeat by the forces of intellectual entropy at a time when new knowledge was coming into the system too fast to be digested or methodized.”
5

Given the hardiness of alphabetical order for so many thousands of years, it will likely remain in use for a long time to come, and parents will continue to beam proudly at their children as they learn to recite the letters in order—something they have been doing to music in the Anglophone world since 1835, when Charles Bradlee published Louis Le Maire's sheet music to “The A.B.C., a German Air with Variations for the Flute with an Easy Accompaniment for the Piano Forte.” (The “German Air” was actually lifted from an eighteenth-century French folksong, which had been adapted by Mozart and had already shown up in English in 1806 as “Twinkle, Twinkle, Little Star.”)

Still, alphabetical order occupies a less prominent place in our lives, especially in reference works, than it once did. Printed reference works need order because their information is spread through space—through pages and through volumes—and readers need help to navigate that space. In the electronic world, though, information takes up only a few molecules on a silicon chip or a few magnetized particles on a hard drive. There is an internal structure of the terabytes of information stored on Google's servers—information must be structured if it's to be found—but it's not as if all the information related to aardvarks and
abacuses is stored on one part of their servers and the information on zydeco and zygotes on another. The user has no reason to care how that information is organized on the hard drives, as long as a query turns up the appropriate information when it is needed. As electronic reference works continue to displace print, and as searches continue to displace browsing, the world may have less reason to care about their ABCs.

CHAPTER
4

ROUND EARTH'S IMAGINED CORNERS

Mapping the World

Some say the cave walls at Lascaux, France, painted around
16
,
500
C.E.
, include star charts. If they are right, cartography has been an obsession of our species since we lived in caves. But even if the dots on Lascaux's walls amount to nothing, maps go back an almost unimaginably long way—more than eight thousand years, long before the first word was written down.

The earliest maps must have involved a truly dazzling act of imagination. For eons, when human beings saw the landscape, they saw it more or less from ground level. They must have climbed trees, hills, even mountains for a better view from time to time. But they always looked
out over
a landscape, never
down on
it. Maps demanded an imaginative leap: the viewer assumes a position no human being had ever actually occupied. Maps show the world as it had been seen only by birds—and the gods. They made it possible to think about physical space in new ways.

We know nothing about these earliest human attempts to capture the contours of their environment on a manageable scale. It is easy to suppose maps were drawn in the sand with a stick or etched in bark, but without evidence, all we have is speculation. Starting in the late seventh millennium
B.C.E.
, though, we have unambiguous examples of cartography. In Catal Hüyük, Anatolia (modern Turkey), archaeologist James Mellaart discovered a map from around 6200
B.C.E.
The nine-foot-long (277-cm) painting on the wall of a shrine, perhaps part of an even larger
map, clearly represents the position of roughly eighty buildings, arranged in terraces, each higher than the one before it. A two-coned volcano, corresponding to the mountain Hasan Dag, appears in the distance, in mideruption, with fire running down its slopes. The locals knew the volcano well, because it was the source of the obsidian they used to make jewelry, tools, and weapons.
1

Over the succeeding eight millennia there have been countless attempts to draw some part of the world, and these graphical “mediators between an inner mental world and an outer physical world” are milestones in our species' intellectual evolution.
2
Maps described faraway coastlines for adventurers and dreamers; they recorded conquests of foreign territory for rulers who needed to keep track of boundaries, whether to police their borders with troops or to collect taxes from the inhabitants. This last is especially important: cartographic advancement was often a byproduct of imperial conquest. Sometime around 324
B.C.E.
, for example, scholars in the employ of Alexander the Great compiled the
Satrapies
, a list of places Alexander had conquered as he expanded his empire. The
Satrapies
began with a strictly administrative purpose but later became guides to geography throughout what was then the known world.

Long before Columbus, people knew the world was spherical. Eighteen hundred years before the
Niña
,
Pinta
, and
Santa María
left Spain, Greek geographers made impressively accurate estimates of the size of the globe. Eratosthenes, for instance, the chief librarian at the Library of Alexandria in the late third century
B.C.E.
, started with the distance between two cities on the same latitude, Swenet and Alexandria: 5,000 stadia. He then performed an ingenious calculation, observing the elevation of the sun in these two cities by measuring shadows, which showed that Swenet and Alexandria were 7° 12' apart—one fiftieth of 360°, and therefore one fiftieth of the way around the earth. The rest of the computation was simple. If 5,000 stadia goes one fiftieth of the way around the earth, then the entire circumference should be 5,000 × 50 = 250,000 stadia. He then adjusted his estimate (for various technical reasons) to 252,000 stadia, the first scientific estimate of the distance
around the whole earth. We don't know for certain how accurate it was, because we don't know exactly how long a stade was. An Attic stade, the Greek standard, was 185 meters, but an Egyptian stade was shorter, about 157.5 meters, and it is unclear which he was using. If he used the Greek measurement, his circumference of the earth came out to 46,620 kilometers—about 16 percent high, not bad for premodern measurement. If he used the Egyptian unit, then his answer was 39,690 km, less than one percent from the actual figure of 40,075 km.

Eratosthenes put all this knowledge to use in his book
Geographike
, an important bridge to modern maps. He divided the earth into zones based on their latitudes: a tropical zone around the equator, a pair of temperate zones to the north and the south of the equator, and a pair of freezing zones at the north and south poles. He then imagined a system of lines running in a grid across the surface of the earth, parallels and meridians, the functional equivalent of the latitude and longitude system that would be used two millennia later, and he used these lines to locate cities on the earth. It was the beginning of systematic geography.

A major development came at the beginning of the common era. The man Klaudios Ptolemaios (or Claudius Ptolemy) is a mystery, and we know neither where nor when he was born or died. He probably began his work in Alexandria, Upper Egypt, in the mid-120s
C.E.
, and he refers to cities founded around 130
C.E.
, so the best guess is that he was born around the year 100. But though we know depressingly little about him, his works on astronomy, astrology, trigonometry, optics, harmonics, and chronology reveal a wide-ranging mind. And his modern translators are to the point: “On any list of ancient scientific works, Ptolemy's
Geography
will occupy a distinguished place.”
3
His
Geography
(also known as
Geographica
or the Greek
Geographike hyphegesis
) was one of the West's first systematic attempts to collect all of the ancient world's cartographic knowledge in one place. Ptolemy was interested in both globes and two-dimensional maps, and he recognized the differences between them, because the three dimensions of the earth can never be represented on a flat surface without distortion.

Although he made observations of astronomical phenomena when he was in Alexandria, Ptolemy was no sextant-toting field cartographer.
Instead, he drew on the combined experience of generations of Greek and Roman cartographers, synthesized it, and made the results available to the world. His
Geographike hyphegesis
is not a map, exactly; rather it is an instruction book for a map, a list of coordinates—thousands of them, from the British Isles to India, China, and Sri Lanka—that, when plotted on a grid, describe a map of the inhabited world. Since it is much easier to copy text (digital information) than images (analog information), Ptolemy's decision to give coordinates gave his book a longevity that no actual map would ever have.
4
Even so, the manuscripts that survive are messy, fragmentary, and sometimes contradictory, so it is no easy feat to put together the text.