Franklin Identifies Lightning 



erecting pointed rods that should rise some feet 

 above the most elevated part, and descend some 

 feet into the ground or water. The effect of 

 these he concluded would be either to prevent 

 a stroke by repelling the cloud beyond the strik- 

 ing distance or by drawing off the electrical fire 

 which it contained; or, if they could not effect this 

 they would at least conduct the electrical matter 

 to the earth without any injury to the building. 

 "It was not until the summer of 1752 that he 

 was enabled to complete his grand and unparal- 

 leled discovery by experiment. The plan which 

 he had originally proposed was, to erect, on some 

 high tower or elevated place, a sentry-box from 

 which should rise a pointed iron rod, insulated 

 by being fixed in a cake of resin. Electrified 

 clouds passing over this would, he conceived, 

 impart to it a portion of their electricity which 

 would be rendered evident to the senses by sparks 

 being emitted when a key, the knuckle, or other 

 conductor, was presented to it. Philadelphia 

 at this time afforded no opportunity of trying 

 an experiment of this kind. While Franklin was 

 waiting for the erection of a spire, it occurred to 

 him that he might have more ready access to the 

 region of clouds by means of a common kite. 

 He prepared one by fastening two cross sticks 

 to a silk handkerchief, which would not suffer 

 so much from the rain as paper. To the upright 

 stick was affixed an iron point. The string was, 

 as usual, of hemp, except the lower end, which 

 was silk. Where the hempen string terminated, 

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