19 Jun 2013
On the rare occasions I get to track down primary sources it can be quite rewarding, and surprising. I've been thinking a bit more about Tobias Mayer recently, which led me to chase up a reference in Nicholas Rodger's The Wooden World. This is to a letter of 4 May 1756 from John Elliot, a young naval officer, to his father. In it, Elliot mentions the recent discovery of longitude by 'a Hanoverian' (i.e. Mayer). The letter's in the archive here in Greenwich, so I had a proper look the other day. This is the passage in question:
And this is how I would transcribe it:
There is no News here worth troubling you with, only the discovery of the longitude by a Hanovarien, it is perform'd by an Observation of the Moon & any fix'd Star by knowing there distance at a given place & observing there diff[erence]e at Sea given the difference of time[. T]he obs[ervatio]n is simple & easey but the Calculation is extreamly perplexd. I had this from a Man that is making the Instrument’
Given the historical run of events, this suggests that news of what the Board of Longitude was doing about Mayer's scheme got out pretty quickly, particularly when we remember that sea trials of Mayer's lunar tables and observing instrument didn't take place for another fourteen months (under John Campbell - but that's another story). The last line particularly intrigues and rather delights me. I think the instrument maker in question is the very important but rather elusive John Bird (another of my obsessions). This would make sense, since Mayer's tables and repeating circle were discussed at a meeting of the Board of Longitude on 6 March 1756, when James Bradley was instructed to have three instruments made for the future tests. Bradley naturally went to Bird, already well known to him from his work at the Royal Observatory. So it seems that within a few weeks Bird was shooting his mouth to a young naval officer. Bird had precious hands but a big mouth, I'd say. I'd love to know more about how his chat with Elliot came about.