17 April 1776, to 'Sir' concerning the committee of meteorology meeting to try the boiling point of different thermometers; seeking support at Royal Society meeting were The Speaker of the House of Commons is being proposed as a member. (The recipient is likely to have been Banks, as letter is included in large bundle of letters to him, but only clue to his identity is that he may own several thermometers by Ramsden)

Administrative / biographical background
Nevil Maskelyne and Joseph Banks were both key members of the Board of Longitude.