1From Benjamin Franklin to Thomas Birch, 4 February 1762 (Franklin Papers)
MS not found; reprinted from The Royal Society, Philosophical Transactions , LII (1761–62), p....
2From Benjamin Franklin to Thomas Birch, 16 April 1762 (Franklin Papers)
AL : British Museum Mr. Franklin’s Compliments to Dr. Birch and returns Mr. Delaval’s and Mr....