# Course:History 344 Nasty Families/Inventions/Slide Rule

### History of the Slide Rule

The slide rule was an early form of the calculator that specialized in multiplication and division. It was invented in the early seventeenth century; The rectangular slide rule in approximately 1620, and the circular rule in 1632.[1] The first slide rule was invented by Reverend William Oughtred. In its earliest form, it was less like the more modern version of the slide rule and instead consisted of two scales that were placed together to the effect of a slide rule.2 These scales were known as Gunter Scales that depicted a logarithm discovered by John Napier. This logarithm allowed for multiplication and division through the use of addition.3 Slide Rules became popular amongst the educated and budding mathematicians as they were a quick way to do complex mathematics.

### Craft

Slide rules were initially engraved on either Ivory or Wood and were used as a type of pocket or handheld medieval calculator. The modern equivalent of the slide rule would not happen for another 300 years, as the reproduction of logarithms first had to be perfected at a high degree.4 The Church played an important role in scientific development, as Oughtred was a British Episcopalian Minister who also had a strong passion for mathematics and science.5

### What it Did

The Slide Rule performs multiplication and division on a basic level. However, its uses extended to the determination of the square root, calculating exponential powers, natural logs, and various mathematical relationships. This would allow for the expedited research and was an important method for discovering the odds and potential earnings of playing the Lottery for example.6

1. Bellis, Mary. About.com, "The History of the Slide Rule." Accessed February 9, 2012. http://inventors.about.com/od/sstartinventions/a/Slidfe_Ruler.htm.�2 The Museum of HP Calculators , "The Slide Rule." Accessed February 9, 2012. http://www.hpmuseum.org/sliderul.htm.�3 Marcotte, Eric. "Introduction of the Slide Rule." Last modified November 03, 2001. Accessed February 9, 2012. http://www.sliderule.ca/intro.htm.�4 Marcotte, Eric�5 Bellis, Mary