1To Benjamin Franklin from Humphry Marshall, 28 May 1770 (Franklin Papers)
ALS : American Philosophical Society I Recieved thy favour of the 18th. of the 3d mo. Last In...
2To Benjamin Franklin from Humphry Marshall, 27 November 1771 (Franklin Papers)
ALS : American Philosophical Society I recieved thy favour of the 22d of the 4th mo. Last in...
3To Benjamin Franklin from Humphry Marshall, 3 May 1773: extract (Franklin Papers)
Extract: the Royal Society Having for some time declined making any more Observations on the dark...
4To Benjamin Franklin from Humphry Marshall, 14 May 1774 (Franklin Papers)
ALS : American Philosophical Society I am Sorry to hear how Matters are Misrepresented at home...