My reviews & how-tos for adding machines and other antique calculating devices.
Curated by: Chris Staecker (120 videos)
The Ott Derivimeter, an instrument for finding the derivative of a curve drawn on paper. Sold by the Ott company in the early 20th century, though I don't know when mine was made. This is episode 84 of my video series about old calculating methods. OTT Hydromet company history video: https://www.youtube.com/watch?v=lgax3bnP-RE Chris Staecker webarea: https://faculty.fairfield.edu/cstaecker #calculus #elsa