the Middle Ages. Coupled to systems of geared wheels, those engines harnessing water and wind powe were used not only to grind grain and move water but also to serve myna HEMISPHERESCOLLIDING • 359 manufacturing purposes, including crushing sugar, driving blast furnace Tellows, grinding ores, making paper, polishing stone, pressing oil, producing salt, producing textiles, and sawing wood. It is conventional to define the industrial Revolution arbitrarily as beginning with the harnessing of steam power in 18th-century England, but in fact an industrial revolution based on water and wind power had begun already in medieval times in many parts of Europe. As of 1492, all of those operations to which animal, water, and wind power were being applied in Eurasia were still being carried out by human muscle power in the Americas. Lone before the wheel began to be used in power conversion in Eurasia, it had become the basis of most Eurasian land transport—not only for animal-drawn vehicles but also for human-powered wheelbarrows, which enabled one or more people, still using just human muscle power, to transport much greater weights than they could have otherwise. Wheels were also adopted in Eurasian pottery making and in clocks. None of those uses of the wheel was adopted in the Americas, where wheels are attested only in Mexican ceramic toys. The remaining area of technology to be mentioned is sea transport. Many Eurasian societies developed large sailing ships, some of them capable of sailing against the wind and crossing the ocean, equipped with sextants, magnetic compasses, sternpost rudders, and cannons. In capacity, speed, maneuverability, and seaworthiness, those Eurasian ships were far superior to the rafts that carried out trade between the New World's most advanced societies, those of the Andes and Mesoamerica. Those rafts sailed with the wind along the Pacific coast. Pizarro's ship easily ran down and captured such a raft on his first voyage toward Peru. inaddition to their germs and technology, Eurasian and Native American societies differed in their political organization. By late medieval or Renaissance times, most of Eurasia had come under the rule of organized states. Among these, the Habsburg, Ottoman, and Chinese states, the Mogul state of India, and the Mongol state at its peak in the 13th century started out as large polyglot amalgamations formed by the conquest of other states. For that reason they are generally referred to as empires. Many Eurasian states and empires had official religions that con-»• uted to state cohesion, being invoked to legitimize the political leader-s »P and to sanction wars against other peoples. Tribal and band societies 360• GUNS, GERMS, AND STEEL in Eurasia were largely confined to the Arctic reindeer herders, the Siberian hunter-gatherers, and the hunter-gatherer enclaves in the Indian subcontinent and tropical Southeast Asia. The Americas had two empires, those of the Aztecs and Incas, which resembled their Eurasian counterparts in size, population, polyglot makeup, official religions, and origins in the conquest of smaller states. In the Americas those were the sole two political units capable of mobilizing resources for public works or war on the scale of many Eurasian states, whereas seven European states (Spain, Portugal, England, France, Holland, Sweden, and Denmark) had the resources to acquire American colonies between 1492 and 1666. The Americas also held many chiefdoms (some of them virtually small states) in tropical South America, Meso-america beyond Aztec rule, and the U.S. Southeast. The rest of the Americas was organized only at the tribal or band level. The last proximate factor to be discussed is writing. Most Eurasian states had literate bureaucracies, and in some a significant fraction of the populace other than bureaucrats was also literate. Writing empowered European societies by facilitating political administration and economic exchanges, motivating and guiding exploration and conquest, and making available a range of information and human experience extending into remote places and times. In contrast, use of writing in the Americas was confined to the elite in a small area of Mesoamerica. The Inca Empire employed an accounting system and mnemonic device based on knots (termed quipu), but it could not have approached writing as a vehicle for transmitting detailed information. THUS, eurasian societies in the time of Columbus enjoyed big advantages over Native American societies in food production, germs, technology (including weapons), political organization, and writing. These were the main factors tipping the outcome of the post-Columbian collisions. But those differences as of a.d. 1492 represent just one snapshot of historical trajectories that had extended over at least 13,000 years in the Americas, and over a much longer time in Eurasia. For the Americas, in particular, the 1492 snapshot captures the end of the independent trajectory of Native Americans. Let us now trace out the earlier stages of those trajectories. HEMISPHERESCOLLIDING • 361 Table 18-1 summarizes approximate dates of the appearance of key developments in the main 'homelands' of each hemisphere (the Fertile Crescent and China in Eurasia, the Andes and Amazonia and Mesoamerica the Americas). It also includes the trajectory for the minor New World homeland of the eastern United States, and that for England, which Ot a homeland at all but is listed to illustrate how rapidly developments spread from the Fertile Crescent. This table is sure to horrify any knowledgeable scholar, because it reduces exceedingly complex histories to a few seemingly precise dates. In reality, all of those dates are merely attempts to label arbitrary points along a continuum. For example, more significant than the date of the first metal tool found by some archaeologist is the time when a significant fraction of all tools was made of metal, but how common must metal tools be to rate as 'widespread'? Dates for the appearance of the same development may differ among different parts of the same homeland. For instance, within the Andean region pottery appears about 1,300 years earlier in coastal Ecuador (3100 b.c.) than in Peru (1800 b.c.). Some dates, such as those for the rise of chiefdoms, are more difficult to infer from the archaeological record than are dates of artifacts like pottery or metal tools. Some of the dates in Table 18.1 are very uncertain, especially those for the onset of American food production. Nevertheless, as long as one understands that the table is a simplification, it is useful for comparing continental histories. The table suggests that food production began to provide a large fraction of human diets around 5,000 years earlier in the Eurasian homelands than in those of the Americas. A caveat must be mentioned immediately: while there is no doubt about the antiquity of food production in Eurasia, there is controversy about its onset in the Americas. In particular, archaeologists often cite considerably older claimed dates for domesticated plants at Coxcatlan Cave in Mexico, at Guitarrero Cave in Peru, and at some other American sites than the dates given in the table. Those claims are now being reevaluated for several reasons: recent direct radiocarbon dat-mg of crop remains themselves has in some cases been yielding younger ates; the older dates previously reported were based instead on charcoal ought to be contemporaneous with the plant remains, but possibly not so, and the status of some of the older plant remains as crops or just as co lected wild plants is uncertain. Still, even if plant domestication did egm earlier in the Americas than the dates shown in Table 18.1, agricul- 3 6 1 •GUNS,GERMS, AND STEEL table18.1 Historical Trajectories of Eurasia and the Americas Approximate Date of Adoption
