Note that Oughtred developed the first slide rules circa 1622, based on earlier work by Gunter and Napier. Pepys mentioned seeing a very small one. https://en.

Note that Oughtred developed the first slide rules circa 1622, based on earlier work by Gunter and Napier. Pepys mentioned seeing a very small one. https://en.wikipedia.org/wiki/William_Oughtred https://en.wikipedia.org/wiki/William_Oughtred