Calculator
Category
Plastics
Date
Unknown
Materials
Metal, Plastic
Measurements
2 mm (Height); 95 mm (Diameter)
Collection
59 Rodney Street, Merseyside
NT 966001
Summary
A flat circular white plastic calculator with blue and black graduated markings, a smaller white plastic movable circle is superimposed and held by a central metal pin.
Marks and inscriptions
The RADIAL Proportional Calculator. To find any proportional width, bring the new length on the inner scale under the original length on the outer scale. The required width can then be read off on the inner scale under the original width on the outer scale.