Uploaded June 2023 | Updated September 2026, 2 weeks ago

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The ACU-ARC Ruler, invented in the 1950s. I'm not sure how old mine is. An instrument for drawing and measuring arcs of circles with specific radius of curvature. Invented by James E Hoyle, manufactured by Hoyle Engineering Company.

This is episode 72 of my video series about old calculating devices.

End song inspired by "Hotter than a Molotov" by The Coup.

Chris Staecker webarea: https://faculty.fairfield.edu/cstaecker

#mustvebeenacrimering

French curves photo by Wikimedia user Radomil, CC-BY-SA 3.0
Pole vaulter photo by Wikimedia Commons user Isiwal, CC BY-SA 4.0