Leiden - Miscellaneous

Miscellaneous

• The coat of arms of Leiden is two red keys, crossed in an X-shape on a white background. These keys are those to the gates of heaven held by St.Peter, for whom a large church in the city center is named. Because of this coat of arms, Leiden is referred to as the "Sleutelstad" ("the key city").
• For a time Leiden held the title "The Coldest Place on Earth" because of the developments in cryogenics in a laboratory there. Heike Kamerlingh Onnes (1913 Nobel prize winner in physics) liquefied helium for the first time (1908), and later managed to reach a temperature of less than one degree above Absolute zero.
• The Norwegian cheese "nøkkelost" ("key cheese") is named after the keys in coat of arms of Leyden, as it is a variation of Leyden cheese.
• The following places and things are named after this city:
  • Leyden, New York, USA
  • Leyden, Massachusetts, USA
  • Leyden High School District 212 in Franklin Park, Illinois, USA.
  • Leiden scale, for measuring extreme low temperatures.
  • Factor V Leiden is named after the city of Leiden where it was discovered in 1994.
  • The Leyden jar, a capacitor made from a glass jar, was invented here by Pieter van Musschenbroek in 1746. It was actually first invented by Ewald Georg von Kleist the year before, but the name "Leyden jar" stuck.