Franklin's Kite

June 1752

In a Philadelphia thunderstorm, Franklin reportedly flew a silk kite tipped with wire and drew sparks from a brass key. The experiment, done quietly and published carefully, proved lightning was electrical. Within a year, lightning rods were sprouting on Boston steeples and churchmen were arguing whether they were impious. The French physicist Thomas-Francois Dalibard had actually performed the experiment first, using Franklin's published instructions.