Lightning Rod

29 July 1750. Philadelphia, PA. Enclosed in a letter to a friend dated 29 July 1750, Benjamin Franklin proposed the use of elevated pointed rods with their lower ends connected to ground to draw off the charge accumulated on clouds in order to prevent lightning discharges. 14 … in some papers attached to a letter of July 29, 1750, to one of his British friends, he [Franklin] proposed the use of elevated pointed rods with their lower ends connected to ground to draw off the charge accumulated on clouds in order to prevent lightning discharges.