I obtained this Unique slide rule Model Universal I from the local car boor sale for £2.
The Unique brand of slide rules was created by Burns Snodgrass (1886–1954).
He was a mechanical engineering lecturer at Brighton Technical College who founded the Unique Slide Rule Company in Brighton, England, in 1920.
Key Facts About “Unique” Slide Rules:
- The Origin: Snodgrass originally started making the rules by hand in his bedroom for his students because they couldn’t find affordable or suitable instruments.
- Affordability: Unlike high-end competitors (like Faber-Castell or Aristo) who used expensive engraving machines, Unique used a “budget-friendly” method. They printed scales onto paper, laminated them with celluloid, and pinned them onto softwood bodies.
- Popularity: Because they were so inexpensive, they became incredibly popular in schools and across the British Empire. It is estimated the company sold over 2.5 million slide rules during its lifetime.
- Evolution: The company remained a family business, eventually run by Burns’ son, Donald Snodgrass. They transitioned to all-plastic designs in the early 1970s but, like most slide rule makers, were put out of business by the arrival of the electronic calculator.
- Legacy: Burns Snodgrass also wrote the famous book Teach Yourself the Slide Rule (1955), which helped generations of students master the tool.
The company officially stopped making slide rules in 1975, though they continued to manufacture other mathematical instruments until the early 1990s.
Sources of Further Information
A more detailed history of fhe company and examples of the types of slides producded is to be found on the Slide Museum website.
A thoroughly researched artricle about the company and its products appeared the The Journal of the Oughtred Society, Volume 6, No. 1, March, 1997 by Peter Hopp et al. A download of this article is available here.
See also examples in the Mathematical Instruments site
A scanned copy of Teach Yourself the Slide Rule is available here