Straight Slide Rule, 1950
- Inventor
- Unknown
- Invention date
- Unknown
- Manufacturing date
- 1950 to 1990
- Manufacturing location
- France
- Manufacturer
- Graphoplex
- Dimensions
- 26cm
- Reference Number
- 116
History and Functionality
The newer straight slide rules are available in three standard scale lengths: 12.5cm, 25cm, and 50cm.
The 25cm slide rule model was the only one authorized in the 1970’s to be used at the French admission exams for scientific schools. The Ministry of Education instructions dated: 7/28/1986 authorizing and recommending the use of electronic calculators during exams ended the use of the slide rule.
The slide rule can do multiplications, divisions, powers and extractions of roots and trigonometric calculations. The back of the rule shows the trigonometric functions: sine, cosine, and tangent in a window.
Slide rules are made of different materials: wood including bamboo and metal including aluminium, ivory, and plastic.
According to GRAPHOPLEX: extensive experiments were conducted to determine the wear of the surface between the mobile part and the fixed part. After 1,500,000 continuous movements of the mobile part with no lubricant at a rate of 37 movements per minute, the wear observed could be considered null.
