Halley's Quest A Selfless Genius and His Troubled Paramore (2005) / Chapter Skim
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Second Voyage 1699-1700: 6 Outward Bound
Second Voyage 1699-1700: 6 Outward Bound
Pages 81-96
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From page 83... ...
Although Halley's call for a new ship had been immediately denied back in July, his request for new officers was fulfilled. Only seven of the original crew returned.
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From page 84... ...
Halley's cabin boy fell overboard. "We brought the ship immediately a stays and heaved out an oar," Halley recorded in his journal.
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From page 85... ...
The relative positions of the Sun, stars, and planets comprise the intricate inner workings of a celestial timepiece. But to tell accurate time using the mechanics of heavenly bodies at sea required clear visibility, a level deck, smooth seas, and at least several hours to calculate it.
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From page 86... ...
. have the effect of exact lunar tables capable to serve at sea, for finding the Longitude with the desired certainty." When other methods failed him, he used this method, as he describes:"Having by my own experience found the impracticability of all other methods proposed for that purpose, but that derived from a perfect knowledge of the Moon's motion." Observing the eclipses and relative positions of the moons of Jupiter and the planet itself was often more helpful -- at least when measured on the steadiness of landfall.
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From page 87... ...
Iago at 23 degrees, 0 minutes west longitude, and 22 degrees, 40 minutes west longitude, respectively, reflect the modern true values. However, once he crossed the equator at the African coast, his measurements were off by about half a degree per day because he failed to factor in westerly equatorial currents, which were imperceptible to him.
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From page 88... ...
Colonization of overseas lands became the easiest way to offset negative trade balances with other countries. In 1650, 1651, and 1660, the English Parliament enacted the Navigation Acts, which by restricting
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From page 89... ...
Halley, arguably a seaman in his own right, had long been interested in advancing England's nautical prowess. In a letter written in 1695 to Samuel Pepys then retired as Secretary of the Admiralty, the administrative head of the Royal Navy, he criticized the "imperfect measure of knowledge in our ordinary navigation." For example, he noted that on a cloudy day sea captains could rely only on soundings to determine their position.
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From page 90... ...
Once ashore, Halley encountered a "Portuguese there with some few Black servants, who assured us there was no salt to be had, the salt pens being all in the water, we had leave to hunt and our people killed and brought aboard two Cabritos [an antelope variety] , one very fat with good meat.
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From page 91... ...
Having carefully examined this observation and compared with former observations made in England, I conclude I am in True Longitude from London at the time of the observations at 30:15." Then on December 9 they "all smelled a very fragrant smell of flowers which the wind brought of the land; and several butterflies flew on board." They reached Rio de Janeiro on December 14 and entered the mountainous harbor then under the governorship of Artur de Sa e Meneses. The Paramore stayed in this enchanting port for two weeks as Halley again enjoyed Portuguese hospitality and the
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From page 92... ...
And because a compass or two were standard equipment on all seagoing ships -- no mariner would be without one -- Halley knew his work could have immediate impact. Familiar with Elizabethan physician William Gilbert's writings circa 1600 entitled De Magnete and the leading discussions since, Halley sought to better understand the invisible forces that made the needle swing.A contemporary of Shakespeare, Gilbert was the first to appreciate the reason a magnetic needle aligns itself roughly north or south along the meridians: terrestrial magnetism.
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From page 93... ...
According to his accounts to the Royal Society, Halley modified his telescope with a reflecting plate, an innovation first conceived by Newton to counter distortions inherent in such refracting scopes. His portable arsenal of devices couldn't compete with the accuracy of the reigning permanent observatories of the day, especially those in Greenwich or Cassini's Paris.
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From page 94... ...
The southern version included maps and directions for the Atlantic islands that Halley was passing in this leg of the mission: the Madeiras, the Canary Islands, Cape Verdes, and the Azores. By the time Halley sailed, one of Seller's rivals, William Fisher, had come out with an English Pilot of his own that covered America and the West Indies.
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From page 95... ...
He procured sandglasses (hourglasses) and sea compasses for the Navy Board.And along with fellow chart maker Joseph Moxon, he served as hydrographer to the king.
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From page 96... ...
. being of two sorts; the one black head and back, with white neck and breast; the other larger and of the color and size of a young Cygnett, having a bill very remarkable hooking downwards, and crying like a bittern." Soon enough other creatures surfaced: "We have had several of the diving birds with necks like swans pass by us, and this morning a couple of animals which some supposed to be seals but are not so; they bent their tails into a sort of bow .
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