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5 unusual facts about Ole Rømer


Danish units of measurement

Towards the end of the 17th century, Ole Rømer, Gerardus Mercator and other contemporaries of the great Dutch cartographer Thisus began following Claudius Ptolemy in connecting the mile to the great circle of the earth, and Roemer defined it as 12,000 alen.

From May 1, 1683, King Christian V of Denmark introduced an office to oversee weights and measures, a justervæsen, first led by Ole Rømer.

Deltoid curve

Ordinary cycloids were studied by Galileo Galilei and Marin Mersenne as early as 1599 but cycloidal curves were first conceived by Ole Rømer in 1674 while studying the best form for gear teeth.

Geographical mile

The Danish and German geographical mile (geografisk mil and geographische Meile or geographische Landmeile, respectively) is 4 minutes of arc, and was defined as approximately 7421.5 metres by the astronomer Ole Rømer of Denmark.

Øster Allé

The stone has, however, nothing to do with Struense being a quarter milestone installed in 1698 in connection with Ole Rømer's survey of Denmark.



see also