## 'Otis King Calculator', cylindrical slide rule, England, 1920-1939

A slide rule is used for multiplication and division of numbers and is accurate to four decimal places. It uses a logarithmic scale which represents numbers as distances along a line. Typically slide rules are straight but the ‘Otis King Calculator’ was designed to have extra length through the use of a spiral along the outside of a cylinder. It was one of the most popular models until slide rules were replaced by electronic calculators in the 1970s. This slide rule was owned by Gwendolen Cartwright (1898-1979), the first woman to be awarded a degree in statistics in England. Her work as a statistician was varied, for instance working for the Eugenics Society on a survey of deprived families in Bethnal Green in London.

#### Object number:

1993-1392

### Related Themes and Topics

## Glossary:

### Glossary: logarithmic scale

A method of representing numbers (certainly positive and usually greater than or equal to 1) by points on a line.

### Glossary: eugenics

The study of human improvement by selective breeding, founded in the 1800s by English scientist Sir Francis Galton. Widely discredited after its use by the Nazi regime.

### Glossary: slide rule

Simple mechanical device used for calculations such as multiplication and division.

### Glossary: statistics

The collecting and classifying of numerical data.