When did Benjamin Franklin supposedly perform his kite experiment?
Kite experiment
Franklin's kite experiment was performed in Philadelphia in June 1752, according to the account by Priestley. Franklin described the experiment in the "Pennsylvania Gazette" in October 19, 1752, without mentioning that he himself had performed it. This account was read to the Royal Society on December 21 and printed as such in the "Philosophical Transactions". A more complete account of Franklin's experiment was given by Joseph Priestley in 1767, who presumably learned the details directly from Franklin, who was in London at the time Priestley wrote the book.
According to the 1767 Priestley account, Franklin realized the dangers of using conductive rods and instead used the conductivity of a wet hemp string attached to a kite. This allowed him to stay on the ground while his son assisted him to fly the kite from the shelter of a nearby shed. This enabled Franklin and his son to keep the silk string of the kite dry to insulate them while the hemp string to the kite was allowed to get wet in the rain to provide conductivity. A house key belonging to Benjamin Loxley was attached to the hemp string and connected to a Leyden jar; a silk string was attached to this. "At this key he charged phials, and from the electric fire thus obtained, he kindled spirits, and performed all other electrical experiments which are usually exhibited by an excited globe or tube." The kite was not struck by visible lightning; had it been, Franklin would almost certainly have been killed. However, Franklin did notice that loose threads of the kite string were repelling each other and deduced that the Leyden jar was being charged. He moved his hand near the key and observed an electric spark, proving the electric nature of lightning.
Owen Beattie
In June 1981, Beattie began the 1845–48 Franklin Expedition Forensic Anthropology Project (FEFAP) when he and his team of researchers and field assistants travelled from Edmonton to King William Island, traversing the island's western coast as Franklin's men did 132 years before. FEFAP hoped to find artifacts and skeletal remains in order to use modern forensics to establish identities and causes of death among the lost 129. In June 1982, a team made up of Beattie; Walt Kowall, a graduate student in anthropology at the University of Alberta; Arne Carlson, an archaeology and geography student from Simon Fraser University in British Columbia; and Arsien Tungilik, an Inuk student and field assistant, were flown to the west coast of King William Island, where they retraced some of the steps of Sir Francis McClintock in 1859 and Frederick Schwatka in 1878–79. Discoveries during this expedition included the remains of between six and fourteen men in the vicinity of McClintock's "boat place" and artifacts including a complete boot sole fitted with makeshift cleats for better traction. After returning to Edmonton in 1982 and learning of the lead-level findings from the 1981 expedition, Beattie struggled to find a cause. Possibilities included the lead solder used to seal the expedition's food tins, other food containers lined with lead foil, food colouring, tobacco products, pewter tableware, and lead-wicked candles. He came to suspect that the problems of lead poisoning compounded by the effects of scurvy could have been lethal for the Franklin crew. However, because skeletal lead might reflect lifetime exposure rather than exposure limited to the voyage, Beattie's theory could be tested only by forensic examination of preserved soft tissue as opposed to bone. Beattie decided to examine the graves of the buried crewmen on Beechey Island. Beattie collaborated with writer John G. Geiger on a book about the researches, Frozen In Time: The Fate of the Franklin Expedition, which became a best-seller in Canada, the United Kingdom and Germany, and has been published in many other countries. The Globe and Mail hailed the book as a "Canadian classic".