This non-commercial website was a 60th birthday present from Ros. The name stems from another family member - our daughter Siân. As a teenager she often told her friends: “My Dad? Oh, he collects expensive sticks of wood!”

When the latest PC/tablet is out-of-date in 6 months it may come as a surprise that the Englishman in the image, the Rev. William Oughtred (1575-1660), invented a calculator around 1621 that would be in continual daily use for nigh on the next 400 years. My hobby is collecting and writing about this analogue calculating wonder - the SLIDE RULE.

This site is a virtual “display cabinet” for my collection (as it gets uploaded) of
slide rules and the odd mechanical calculating aid plus a “bookshelf” for my published articles - enjoy browsing.

To learn more about the history of this remarkable calculating wonder check out the “Slide Rule History” by the Oughtred Society or my 2-page summary (in Dutch!).

Anyone needing a “memory jogger” or is just intrigued how such analogue calculators of the past worked, the International Slide Rule Museum has a richly illustrated “How to use …” guide. Afterwards try doing a few trial calculations with Derek Ross’ online simulation of a Pickett N909-ES slide rule. Thinking of starting your own collection? Then the Oughtred Society’s Beginner’s Guide to Collecting Slide Rules is the place to start.

Educators looking for maths related inspiration & teaching aids/material need look no further than Nicola Marras’ website. But if just looking for reference books on slide rules try one of these: MyList 1 or MyList 2 .