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    Re: CN and Mason-Dixon line
    From: Francis Upchurch
    Date: 2013 Nov 26, 23:55 -0800

    Bruce, I agree.I'm studying the much maligned Maskelyne astronomer Royal.
    Apart from his pioneering work with lunars, (Mariners Guide, later Nautical almanac, )he also was the first to measure the mass of the world. An amazing achievement for its time (got the Copely medal FRS, equivalent to tdays Nobel) Se this http://www-history.mcs.st-andrews.ac.uk/Extras/Maskelyne_Schehallien.html
    In 1775 Nevil Maskelyne wrote two papers on the mountain method of measuring the Earth's density which appeared in the Philosophical Transactions of the Royal Society. Below are extracts from these papers, the first of which was his proposal to the Royal Society made in 1773, and the second of which was his report which led to the award the Copley medal of the Royal Society:-
    He really was an amazing astronomer and mathematician. got very bad press from Sobel et al re Harrison I think.On a similar note, Numerous lunars for longitude were done by purser Harrison (no relation) on the Dolphin Yoyage, prior to Cook's Endeavour voyage and prior to the Nautical Almanac.He used the Mariners guide, 4 hour method for clearamnce and Cook already had accurate longitudes from Dolphin, up to Tahiti! reference from Wales 1788, see attached.There's more in the Cambridge library on digital.
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