Simson on Porisms

Most mathematicians'' knowledge of Euclid''s lost work on Porisms comes from a very brief and general description by Pappus of Alexandria. While Fermat and others made earlier attempts to explain the Porisms, it is Robert Simson who is generally recognised as the first person to achieve a genuine insight into the true nature of the subject.
In this book, Ian Tweddle, a recognised authority on 18th ...