We are in May 1780, M. De Vissery de Boisvallé was a lawyer from Saint-Omer but also a physicist, painter and botanist. This avant-garde scientist was the author of various mostly unknown inventions, one of which consisted of the corruption-free preservation of fresh water for more than a year. This lover of new scientific experiments was seduced by Benjamin Franklin’s invention of the lightning rod. It was therefore natural that he established an electrical conductor on the chimney of his house, one of the first in France, which was precisely a golden sword blade, screwed onto an iron bar, 16 feet long at the time (about 5 meters).
A neighbor went to complain to the town bailiff about this installation considered an invention of the devil and before De Vissery could defend himself, the aldermen ordered the removal of this dangerous object within 24 hours. Nevertheless, De Vissery was resourceful and brought the case before the Council of Artois. He was then represented by a young lawyer from Arras: Maximilien de Robespierre. The debates open in May 1783.
With a very well-referenced file from the Academy of Sciences, testimonies from Beaumarchais and Benjamin Franklin, the lawyer from Arras wins the trial, which will participate in his burgeoning fame. De Vissery reinstalls his lightning rod under the nose of the aldermen and his neighbor.