From Isaac Winn8
ALS: the Royal Society
[Before February 1, 17701]
Tis a common and I am afraid just complaint, that Seamen are exceedingly backward in availing themselves of the discoveries which Men of Science have made, and the directions which they have given for their benefit and safety. Notwithstanding the pains several eminent Philosophers have taken, to bring Conductors into general use, as well in Ships as houses, ’tis too true that very few Vessells are furnish’d with them, tho’ scarce a year passes that does not afford us Instances, (some of them terrible ones) of Ships being struck by Lightning. For my part I am never without a Conductor in my Ship. I have had them of various constructions: that which I now use is a Chain of copper wire as described in the annex’d plate: that such a Chain, so disposed may conduct the lightning, and prevent a Stroke that might destroy a Ship, has often been demonstrated: but a circumstance that occurred in my last Voyage may perhaps have greater weight with some Seamen than all the reasoning of the Electricians: If it should be a means of perswading them to make use of Conductors my Intention will be answer’d. In April last, as we approached the Coast of America we met with strong Southwesterly Gales: they had continued several days, when exceeding dark heavy clouds arose in the opposite quarter, forced against the wind that blew with us till they had cover’d all the North Eastern half of the Hemisphere; the Struggle then between
I. L. Winn
References to the Plate
Endorsed: Capt. Winn’s Acct. of the Appearance of Lightning in his Conductor. Received Feb. 1, 1770. March 2 A Letter to Dr. Benjamin Franklin giving an account of the appearance of lightning on a conductor fixed from the summit of the mainmast of a ship Down to the water by Capn. I. L. Winn.
8. A merchant captain, master of the Dutchess of Gordon. See N.- Y. Gaz. (Gaine), May 8, 15, 29, 1769.
1. The letter cannot be accurately dated. The voyage to which it refers began in the Downs on March 7 and ended at New York on April 24, 1769. Ibid., May 1, 1769; Pa. Gaz., May 18, 1769. Winn returned to England, and crossed again later in the year: he left for New York in the early autumn, arrived there in November, and cleared again for London before the month was out. PMHB, LX (1936), 472; N.- Y. Gaz. (Gaine), Nov. 20, 1769; N.- Y. Jour., Nov. 30, 1769. He might have written the account at sea during this second voyage, from which he would have returned to England in ample time to deliver his letter to BF on Feb. 1, 1770, for transmission to the Royal Society. It was read there on March 29 and published (with Winn’s initials incorrectly given as J. L.) in Phil. Trans., LX (1770), 188–91; a few words lost in the MS have been silently restored from the printed text. BF’s interest in apparently similar phenomena went back for twenty years. See above, III, 473; IV, 143.]
2. The drawing that accompanied the original has been lost, although Winn’s references to it at the end of the letter survived. Our illustration is reproduced from a broadside in the Yale University Library and contains, it will be noted, two lines of reference that Winn must have added later.