Dual rule CASTELL 67/54 R
- Inventor
- Unkown
- Invention date
- Unkown
- Manufacturing date
- Unkown
- Manufacturing location
- Germany
- Manufacturer
- AW FABER CASTELL
- Dimensions
- L 15
- Reference Number
- 117
History and Functionality
The purpose of this rule is to provide a single instrument for the four operations.
This instrument is the juxtaposition of two instruments. It consists on one side of a straight adder dedicated to additions and subtractions of numbers up to 6 digits. On the other side is a straight slide rule with a 12.5cm scale for performing products.
A lever is used to reset quickly to 0 the figures set on the adder.
The operator reports the values between the adder and the straight slide rule.
