Archive
of
Collections
Details and Image
Type
Model No.
Maker
Country
Construction
Material
Date
Scale Length
Area of Use
Circular and Spiral Slide Rules
Dempster / RotaRule - AA
J.R. Dempster
USA
Plastic
1933-1948
Ø 13 cm
Complex calculations
Notes:
Copyrighted 2nd generation AA model (3 extra scales) with a 127 cm long-scale. Based on patented designs (US1868816 and US1849058) from 1932.
Image 1
Image 2
Image 3
Image 4
Image 5
Image 6
Image 7
