Hollow Earth: The Long and Curious History of Imagining Strange Lands, Fantastical Creatures, Advanced Civilizatio Read Free

divers kinds.”
    Major advances in precision clock making were also ticking along, another component in this surge of technical innovation and an important part of the scientific revolution itself, since much of what was being studied depended on accurate measurement of time—especially in relation to astronomy, navigation, and surveying. Clocks before the seventeenth century were large, crude devices that never kept anything close to true time. The minute hand wasn’t added until 1670. In 1582 Galileo had observed the timekeeping properties of pendulums, and in 1656 Dutch astronomer and physicist Christian Huygens applied this principle to clock making with notable results. In 1675 he had one of those eureka! moments, thinking of a way to regulate a clock using a fixed coiled spring. This innovation led to smaller watches (though the often contentious Robert Hooke complained that he’d made a spring-regulated clock ten years earlier) that could be used onboard ships, since calculating exact time was the crucial missing component in the search to establish accurate longitude.
    Much of this new scientific activity, especially in regard to astronomy and improvements in clock making, was being driven by economic and military interests, as were Halley’s speculations on the hollow earth.
    In the seventeenth century England became a true maritime power. From the time of the Restoration (1660) onward, English shippers began rivaling the Dutch, the world’s greatest traders. In the many tangled wars that bloodied the century (between 1650 and 1700, for instance, the English fought three wars against the Dutch and were allied with them in a fourth against the French), the sceptered isle was duking it out with rivals on the open seas and putting together a colonial empire with far-flung holdings the world over. (One notable addition came in 1664, when they seized New Amsterdam from the Dutch and renamed it for the duke of York.) This meant more and more ships crisscrossing the oceans. Naturally they all had to know where they were and where they were going, as any miscalculation could lose money and lives. All those sunken wrecks full of lost plunder are tribute to what was at stake.
    Determining latitude was a breeze, achieved by taking an angle on the sun or the polestar. But longitude was a bitch. Theoretically the easiest way to determine longitude was to establish a universal time at a prime meridian and then compare that to local time, applying a simple formula to calculate the distance from the prime meridian. But accurate clocks wouldn’t exist until well into the next century, when John Harrison developed his famous watch and finally, after much cheap dodging on the Royal Society’s part, won the celebrated Longitude Prize of £20,000 (about $12 million today), which had gone begging for fifty years. Until then, the next best thing was fanatically detailed astronomical tables.
    In the seventeenth century, astronomy was a weapon in the national arsenal. For example, in 1675 King Charles II was persuaded to okay funding for the Greenwich Observatory. He did this because the sneaky, underhanded French had built one, and he didn’t want England to be faced with an observatory gap! The first scientific institution in Great Britain, it was essentially built as a military installation. The money came from the budget of the Ordnance Department, which, as Lisa Jardine observes, was the Restoration equivalent of the Pentagon. The goal was greater accuracy and detail in astronomical charts—pinpointing the positions of the stars, the moon, and even the moons of Jupiter. Prior to trustworthy seagoing chronometers, celestial bodies were the most reliable way of determining longitude, distant clocks shining in the nighttime sky.
    In 1676 twenty-year-old Halley left Oxford without graduating and eagerly journeyed to the island of St. Helena, a patch of land belonging to the East India Company located 1,200 miles west of Africa’s