Normal sparking from an electrical outlet. When that power is suddenly diverted to an appliance, there will be a quick draw on the available power, causing a brief spark. Once the electrons are flowing freely, there should be no reason for a spark to form.
Alfred Kastler (3 May 1902 â 7 January 1984) was a French physicist, and Nobel Prize laureate.
If you mean who introduced the symbol pi in the public it was Euler.The following article though says a different story. William Jones and his Circle: The Man who invented Pi.