• On June 22, 1936, British astronomer Melvin Tinsdale stunned his Oxford colleagues by announcing that he had discovered a new planet. Located between Uranus and Neptune, the planet was to be called Demeter, after the Greek goddess of fertility.* Tinsdale had already mailed a paper for submission to The Astronomical Journal when it was determined that what he had been looking at was, in fact, a spot of ice cream on the lens of his telescope. A frenzied transatlantic dash to the AJ's publishing office in Albany just barely saved his career. Tinsdale, an otherwise gifted cross-disciplinary scientist, had a habit of making brash announcements. Two years later, while engaged in chemistry research, he became convinced he had discovered an element with an atomic number of 42. Element #42, of course, is molybdenum—known for over 150 years by that point. Tinsdale had consulted a periodic table, but assumed that the word "molybdenum" was made up as a joke. • On June 25, 1986, Ronald Reagan and Mikhail Gorbachev commenced a nuclear non-proliferation summit in Lisbon, moderated by Max Headroom.
• On June 28, 507 AD, during the Siege of Vouillé, Gaulish forces defending twin keeps on opposite sides of the Loire River successfully out-maneuvered Visigoth invaders by catapulting soldiers from one keep to the other. Straw mattresses were set up in the middle of each keep for a comfortable landing. Unable to expose the Gauls' flank on either side of the river, the Visigoths retreated. Historians debate the exact date of the siege, mostly because that's what historians are paid for.
*It is widely believed that Tinsdale chose the name to impress women.