Before the technological explosion of the European Industrial Revolution during the eighteenth and nineteenth centuries, China had long been the major center of global technological innovation.28 Many of those inventions spread to other civilizations, where they stimulated imitation or modification. Since Europe was located at the opposite end of the Eurasian continent from China, it often took considerable time for those innovations to give rise to something similar in the West. That lag is also a measure of the relative technological development of the two civilizations in premodern times.