Special Exhibition Label: 'Geek is Good' (15 May - 2 November 2014) - Slide rules general introduction
When Slide Rules Ruled
Slide rules were pre-eminent instruments of practical calculation for 350 years. Held in the hand or worn at the waist they were a symbol of the engineer in the 20th century.
This giant example was used for classroom teaching; its corresponding regular-sized version was portable, with scales 25cm long. It was probably made in about 1970, just before slide rules began to be challenged by portable electronic calculators.
All slide rules have a fixed body and at least one moving slide. In the version above, the central ruler can slide left and right while the outer two are fixed. The scales which cover the surfaces are based on logarithms – and there are just as many additional scales on the other side of the example above. It also has a sliding cursor so that a user can read from one scale to another even if the scales are not adjacent.
Slide rules do not add or subtract, but can perform multiplication and division and, with the right scales, a host of other more advanced calculations from powers and roots to trigonometry. While straight rules were the most popular variety, slide rules were also made in circular and cylindrical forms.
Teaching the slide rule: an American school class of the 1930s with a demonstration rule on the blackboard. Note that the pupils all have their own slide rules. (Smithsonian Institution Libraries)
The Love of Slide Rules
Although slide rules are no longer widely taught and used, they are still a focus of attention. The United Kingdom Slide Rule Circle (UKSRC) was formed in the mid-1990s as an informal group of enthusiasts interested in the history, manufacture and collection of slide rules. There is a programme of meetings and a regular newsletter with an international readership. Contacts and collaboration are maintained with equivalent organisations such as the Oughtred Society in the U.S.A., the Dutch Kring Historische Rekeninstrumenten and the German Rechenschieber-Sammler-Treffen. There is also an annual Slide Rule Gazette for more substantial research articles.
The UKSRC welcomes new members and is always available to assist in slide rule related queries. Contact colinabarnes@talktalk.net or visit the website at www.uksrc.org.uk.
Other narratives:
- Inventory No. 40847 & 35515 - Exhibition Label Text 'The Double Horizontal Dial: Then and Now' 13 January to 10 March 2009
- Inventory no. 40847 - Former Display Label
- Bennett, J. and Johnston, S., The Geometry of War, 1500-1750 (Oxford, 1996)
- Movable parts
- Circles of proportion
- Special Exhibition Label: 'Geek is Good' (15 May - 2 November 2014)
- Reverse prints taken from this instrument
Related Objects:
- Inventory No. 40847, "Circular Slide Rule and Horizontal Instrument, by Elias Allen, London, c. 1634" [1924-32], Allen, Elias
- Inventory No. 49249, "Suxspeach Universal Slide Rule, by Ben Parker, Ratcliff, 1753" [1924-0/part], Parker, Ben, Suxspeach, John
- Inventory No. 88568, "Instruction Booklet "The Fuller Calculator", by George Fuller" [1994-2/1]
- Inventory No. 88568, "Fuller's Helical Slide Rule, by W. F. Stanley, English, 20th Century" [1994-2/1], W. F. Stanley & Co. Ltd.