## history of mathematics

**Isaac Newton**and David Gregory - took place on the campus of Cambridge University. The discussion concerned the

**kissing problem**, but it was to be another 260 years before the problem was finally solved.

**Bill Casselman**writes about the intriguing amateur mathematician Henry Perigal, who took his elegant proof of Pythagoras' Theorem literally to his grave - by having it carved on his tombstone.

**J.V. Field**continues our series on the origins of proof with an examination of Kepler's astronomy.