Benjamin Franklin is credited as being the first person to propose an iron lightning rod as a way of drawing electricity from clouds and thereby proving that clouds are electrically charged. But according to my various weather textbook references, others actually constructed the first rod and tested it.
Franklin may not have understood the value of the rod as a way of protecting property. He most certainly underestimated the danger posed by lightning. In his experiment, Franklin directed that a man should be placed inside a small enclosure, gripping the rod as way of verifying the charge. Several people who followed this advice were electrocuted while trying to conduct his experiment. In the end, however, Franklin's theories on electricity proved correct and advanced the study and understanding of the phenomena.