The Day the World Discovered the Sun Read Online Free PDF Page B

comparing the moon’s position in the sky to its predicted position from navigational tables printed months in advance. One of the prodigies working on these very tables was a West Country boy whose name would one day divide a nation.
O FFSHORE OF S ALCOMBE , E NGLAND
January 9, 1761
    Charles Mason squinted through the early morning light to make out the cove where the Ramillies had crashed ashore just eleven monthsbefore. Mason’s ship, the HMS Seahorse , creaked the easy groan of a frigate cutting a line through the English Channel.
    The Seahorse hadn’t even been under sail for twenty-four hours. But disquieting recollections of a treacherous coastline to starboard begged the question: How soon till we set a course toward the open Atlantic? The coming day would in fact be the last day Mason could lay eyes on English land for more than a year.
    Mason and his assistant, Jeremiah Dixon, were making hasty passage to Bencoolen, Sumatra (today Bengkulu, Indonesia) to observe the June 6, 1761, Venus transit.
    Mason, 32, had made a reputation among Gloucestershire schoolmasters and tutors as a mathematical wunderkind. England’s Astronomer Royal, James Bradley, hailed from the same county and through local connections learned about Mason’s prowess. Bradley hired Mason in 1756 as an assistant at the Royal Observatory in Greenwich.
    Dixon, 27, was the son of a wealthy coal mine owner near Newcastle-upon-Tyne who began his career as a surveyor but showed remarkable talent at both math and astronomy. Dixon’s skills impressed a family friend, one of Bradley’s top instrument makers, enough to recommend the surveyor when the Royal Society began casting about for someone to assist Mason on his 1761 Venus transit voyage.
    The East India Company operated a factory in Bencoolen that, as one contemporary visitor put it, “produces some drugs, but chiefly pepper.” 2 The factory town was going to be their new home and site of an astronomical observatory of their making. The company had promised to cover Mason and Dixon’s “diet and apartments” in Bencoolen and “whatever else the service they are employed upon may require.” Plus the company would cover all expenses for the observers’ passage home. All their services expressed, as a company memo to the Royal Society put it, that this profit-oriented corporation was “extremely desirous of contributing every thing in their power for facilitating the making of observations upon the transit of Venus.” 3
    Mason and Dixon, who had never met before the Royal Society paired them up for this voyage, were promised £200 each ($50,000 in today’s money) to venture 14,000 miles around Cape Horn and through the Indian Ocean to their Pacific destination. Neither had traveled more than three hundred overland miles from home before. And home, for both of them, meant some heavy freight to be left behind. Mason was a recent widower, with two sons whose care he had to arrange for in his absence. Dixon was a tippler—having been kicked out of his Quaker congregation for excessive drinking just three months before.
    As seamen manned the first night watch, Seahorse sailed through the icy waters of the channel toward a rare alignment of the moon and planets. Within 40 degrees of one another in the southwestern sky lay Venus, Mars, Jupiter, Saturn, and a sliver of a crescent moon. Both Mason and Dixon had earned their place on this voyage as meticulous watchers of the night sky. Mars shined near the horizon, south by south-west, separated from Venus by 10 degrees and 29 arc minutes. Jupiter practically sat atop Venus, a mere 3 degrees and 6 arc minutes distant in the sky. Both hugged the upper edges of the moon’s crescent. 4
    The Astronomer Royal’s instructions for observing the Venus transit once they’d landed at Bencoolen called for both timing the duration of the transit and making angular separation measurements