Chasing a Dream by John Dunmore

Author:John Dunmore
Language: eng
Format: epub
Publisher: Upstart Press
Published: 2016-03-19T16:00:00+00:00

10

The Great Navigator

The heights by great men reached and kept

Were not attained by sudden flight,

But they, while their companions slept,

Were toiling upward in the night.

Henry Wadsworth Longfellow, “The Ladder of St Augustine”

When the Astronomer Royal Edmund Halley died in 1742, at the ripe old age of 86, he bequeathed a dream to the Royal Society. He knew he would not live long enough to see the transit of Venus across the sun in 1761, or even to organise expeditions to various parts of the world to observe this infrequent phenomenon, but he urged all his fellow scientists to make sure that it would not be missed. When the planet passed across the sun, observations made from two or more points on the globe would enable astronomers to work out the distance between the earth and the sun. These transits occur in pairs only every century or so, and the information that would be gained was important, particularly now that it was so much easier to sail to distant places.

His fellow scientists agreed with him, and not only in Great Britain. The French Académie des Sciences was determined to play its part in what could be a cooperative European endeavour. The astronomer Joseph-Nicolas Delisle drew up a plan for a set of observations to be taken from various parts of the globe from China to the Cape of Good Hope and the shores of North America. He wrote tirelessly to noted scientists in Britain, Sweden, Germany, Russia and elsewhere, hoping to unite them in a grand scheme. Their reports could then all be collated into one comprehensive study. Their countries, sadly, were too often at war for this to be practicable. The result was a piecemeal effort by a few scientific groups. In 1760, the French Académie despatched Alexandre-Guy Pingré to Rodriguez Island in the Indian Ocean, where he managed to carry out some not very satisfying observations, only to be marooned on the island after an English raid. Another Frenchman, a talented young man named Le Gentil de La Galaisière, went to Pondicherry, only to find out that it was now in British hands. He did carry out some observations on board his ship, but the sea was rough, the weather partly cloudy, and the attempt was not very successful. Determined to have another try on the occasion of the second transit in 1769, he spent eight years in the Philippines, China and other places. Pondicherry had been given back to the French, so he was able to land there for his observations, but the weather was overcast and he failed again. When he finally got back to France with a crateful of notes and reports, he had been totally forgotten and his heirs were arguing over his estate. For their part, the British had sent Nevil Maskelyne to St Helena, while Nathaniel Bliss worked as best he could at Greenwich Observatory.27

The second transit was far more successful, largely because the various governments took the urgings of their respective societies more seriously and the great Seven Years War had come to an end.

Download

Copyright Disclaimer:
This site does not store any files on its server. We only index and link to content provided by other sites. Please contact the content providers to delete copyright contents if any and email us, we'll remove relevant links or contents immediately.