Halley's Quest A Selfless Genius and His Troubled Paramore (2005) / Chapter Skim
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7 Terra Incognita
7 Terra Incognita
Pages 97-110
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From page 97... ...
On January 31 the Paramore reached the farthest point south ever recorded by an expedition at the time, latitude 52 degrees, 24 minutes south, but for the first time Halley distrusted his measurements. Another bed of weeds -- often a sign that land or shallow waters were near -- floated by the ship.
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From page 98... ...
Halley estimated the height of the first island to be close to that of the real Beachy Head in Eastbourne Downland. At 530 feet it is England's highest chalk sea cliff.
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From page 99... ...
By the time Halley realized the so-called islands were colossal floating icebergs, his Paramore was in harm's way. Once again, the world had proven not to be as it seemed -- even the visible world of their common senses betrayed the crew and their elite navigator and diligent scientist.
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From page 100... ...
Halley headed north toward his old stomping grounds of St. Helena, where he'd spent that seminal year as a student, and made for Tristan da Cunha, a remote, uninhabited cluster of islands of volcanic origin midway between South America and South Africa.
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From page 101... ...
While en route in the chill Benguela current, a violent squall erupted on February 26 that "threw us so that we had liked to have overset, but please God. She righted again." Although leaks, perhaps aggravated by cold waters, had spoiled six dozen loaves of bread and 30 pounds of flour and cheese, Halley refused to return directly to England "fearing to go home in the winter, which would expose my weak ship's company to great hardships." On March 11 they made St.
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From page 102... ...
In a 1691 paper Halley presented his idea to the Royal Society on using transit timings from several distant locations on Earth to accurately calculate the Earth to Sun distance. Readings from different sites would help astronomers pinpoint the timing of the end and the start of the egress, the period when Venus moves inside the limb of the Sun.
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From page 103... ...
A Royal Society commission secured King George III's approval for an expedition to Tahiti to do exactly that. Based in large part on Halley's proposals, the mission was led by Lieutenant James Cook aboard the Endeavour.
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From page 104... ...
At the time of Halley's birth in about 1656, the Copernican revolution in astronomy was at least a century old and nearing acceptance in mainstream thought. About this time at the French Academie, the Dutch vanguard Christiaan Huygens built the first efficient pendulum clock, key for measuring time at night at remote locations.
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From page 105... ...
The technology to expand on his premise wouldn't be developed for another 150 years. The limitations of the precision of the instruments then available also prevented the successful measurement of a single accurate stellar distance in Halley's lifetime, though that didn't stop Cassini and others from making triumphant claims that they had made accurate determinations of such distances.
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From page 106... ...
In fact, on some observations Halley and Hevelius, working to find star positions in tandem on a six-foot sextant with both a movable and a fixed sight, attained an accuracy within five seconds, or twice as accurate as Flamsteed claimed with his telescopic sights. In Halley's absence, Hevelius often observed the night sky with his second wife, Catherine Elisabeth, a reputed beauty 36 years his junior.
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From page 107... ...
"I offer myself voluntarily as a witness of the scarcely credible certainty of your instruments, against anyone who shall hereafter call the truth of your observations into question," Halley wrote. Hevelius's observations may have been more accurate at that time and place, but telescopic sights would soon be shown to unequivocally afford finer resolution and greater accuracy than the unassisted human eye.
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From page 108... ...
"Anyhow she will be able to preserve it until her period of mourning is past." All of London learned several months later that Hevelius had survived the fire, but the catastrophe did not stop proponents of telescopic sights from raging on with their technology crusade, nor did it stop Flamsteed, when it would suit his political agenda, from later using the silk dress as evidence of some sort of indiscretion on Halley's part. His insinuations seemed plausible enough.
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From page 109... ...
Hooke's rivals in the Royal Society, including John Wallis, relished whatever collateral damage might result from such invective. Meanwhile, Halley cleverly let the proverbial chips fall as they may.
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From page 110... ...
"The island being about 1.5 leagues in length, lying nearest NW and SE. The North and West part is nothing but steep rocks scarce accessible." Pleasantly surprised with the unpopulated piece of real estate once ashore, he thought the island, with its bountiful water supply, would be a valuable resupply point for English ships.
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