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Transit of 1761, Part III

June 8, 2011

In December of 1760, the British naval vessel HMS Seahorse was attacked by a French warship just hours after leaving home. It limped back to port with 11 dead, more than 30 wounded, and two passengers who were ready to pack it in -- Charles Mason, an assistant to Britain's astronomer royal, and Jeremiah Dixon, a surveyor and amateur astronomer.

The ship's destination was Sumatra. There, in June of 1761, Mason and Dixon would observe a transit of Venus across the face of the Sun. Combined with observations from other locations across the globe, their work would help astronomers measure the distance to Venus, which in turn would tell them the distance to the Sun.

After the attack, though, Mason and Dixon tried to abandon their expedition. But the Royal Society, which chartered and funded the trip, would have none of it. It threatened both men with lawsuits and financial ruin. So they quickly reconsidered, and headed back out to sea in early 1761.

They never made it to Sumatra, though, because France had captured their intended destination. So instead, Mason and Dixon watched the transit from Cape Town, South Africa. And despite the tribulations, their observations were superb.

In fact, just a couple of years later, their work earned them a new assignment: surveying a dividing line between American colonies -- the Mason-Dixon Line.

More about the transit tomorrow.


Script by Damond Benningfield, Copyright 2011


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