Editing Pendulum (section)

=== Britain and Denmark ===
Britain and Denmark appear to be the only nations that (for a short time) based their units of length on the pendulum. In 1821 the Danish inch was defined as 1/38 of the length of the mean solar seconds pendulum at 45° latitude at the meridian of [[Skagen]], at sea level, in vacuum.<ref>{{cite journal
  | last = Schumacher
  | first = Heinrich
  | title = Danish standard of length
  | journal = The Quarterly Journal of Science, Literature and the Arts
  | volume = 11
  | issue = 21
  | pages = 184–185
  | year = 1821
  | url = https://books.google.com/books?id=KwEXAAAAYAAJ&pg=PA184
  | access-date = 2009-02-17}}</ref><ref>{{cite encyclopedia
  | title = Schumacher, Heinrich Christian
  | encyclopedia = [[The American Cyclopedia]]
  | volume = 14
  | pages = 686
  | publisher = D. Appleton & Co., London
  | url =https://books.google.com/books?id=OlJMAAAAMAAJ&pg=PA686
  | year = 1883
  | access-date = 2009-02-17}}</ref>  The British parliament passed the ''Imperial Weights and Measures Act'' in 1824, a reform of the British standard system which declared that if the prototype standard [[yard]] was destroyed, it would be recovered by defining the [[inch]] so that the length of the solar seconds pendulum at London, at [[sea level]], in a vacuum, at 62&nbsp;°F was 39.1393&nbsp;inches.<ref>{{cite book
  | last = Trautwine
  | first = John Cresson
  | title = The Civil Engineer's Pocket-Book, 18th Ed
  | publisher = John Wiley
  | year = 1907
  | location = New York
  | page = 216
  | url = https://books.google.com/books?id=qg41AAAAMAAJ&pg=PA216
  }}</ref>  This also became the US standard, since at the time the US used British measures. However, when the prototype yard was lost in the [[Burning of Parliament|1834 Houses of Parliament fire]], it proved impossible to recreate it accurately from the pendulum definition, and in 1855 Britain repealed the pendulum standard and returned to prototype standards.