This letter (really, an extended paper) by the American founding father and 18th century scientist Benjamin Franklin FRS (1706-1790) was addressed to the physician and chemist William Brownrigg FRS (1711-1800). Franklin, in company with the Royal Society’s President Sir John Pringle (1707-1782), had visited Brownrigg during a tour of Britain in 1772. Brownrigg’s home was conveniently close to Derwentwater in Cumbria providing an opportunity for the experiment (and piece of showmanship) with which Franklin entertained many of his friends; pouring oil on troubled waters.
“Of the stilling of waters by means of oil”, a compendium of letters and commentary was published in the 1774 'Philosophical Transactions'. In it, Franklin’s letter (reproduced in full here) lacked its charming preamble. This introduction has Franklin offering humorous encouragement to his host’s wife, Mrs Mary Brownrigg, in the making of parmesan cheese before the more serious scientific business. The paper itself commences with Franklin first observing the quietness of the ocean after greasy water had been emptied overboard during a sea-voyage; then rather more systematically gathering anecdotes to support the idea that oil might have a practical effect. The stories include the smoothness of the sea around the whaling vessels of Newport, Rhode Island. He also marshals evidence from those most practical men, the civil engineers John Smeaton FRS (1724-1792) and William Jessop (1745-1814), with that of the naval officer and inventor Captain John Bentinck (1737-1775) on aspects of the phenomenon. The climax of the paper is a full trial at Portsmouth of Franklin’s idea of using oil to calm waves, allowing a small boat to land safely in otherwise rough surf.
Franklin’s writing style is, as always, precise and scientific but also discursive, familiar and entertaining. He remains one of the most approachable scientific writers.