For Whom the Bells Toll
In the early 1750s, Franklin erected a lightning rod on top of his house for the purposes of experimentation, protection and, perhaps, to get electricity for experimentation without having to go through the laborious process of creating it himself via a primitive battery.
Franklin's "iron rod" drew lightning down into his house. The rod was connected to a bell and a second bell was connected to a grounded wire. Every time there was an electrical storm, the bells would ring and sparks would illuminate his house.
Franklin described the experiment as follows. The rod was:
"fixed to the top of my chimney and extending abut nine feet above it. From the foot of this rod a wire (the thickness of a goose-quill) came through a covered glass tube in the roof and down through the well of the staircase; the lower end connected with the iron spear of a pump. On the staircase opposite to my chamber door the wire was divided; the ends separated about six inches, a little bell on each end; and between the bells a little brass ball, suspended by a silk thread, to play between and strike the bells when clouds passed with electricity in them. After having frequently drawn sparks and charged bottles from the bell of the upper wire, I was one night awakened by aloud cracks on the staircase. Starting up and opening the door, I perceived that the brass ball, instead of vibrating as usual between the bells was repelled and kept at a distance from both; while the fire passed, sometimes in very large, quick cracks from bell to bell, and sometimes in a continued, dense, white stream, seemingly as large as my finger, whereby the whole staircase was inlightened with sunshine, so that one might see to pick up a pin."
Legend has it that Franklin's wife, Deborah, was so flustered by the ringing bells and flashing lights, that she wrote to her husband who was off in London, asking him how to disconnect the experiment.
