Royal Society & Isaac Newton, inventor of the cat flap

Sandi Toksvig interviews John Gribbin, who has just written a book about the Royal Society, "The Fellowship: The Story of a Revolution". Join Sandi -- solicitor, novelist, traveller, raconteur -- for her refreshing and at times irreverent perspective on the world. Each day she is joined by a regular chum and the team -- here to bring you the perfect lunch. Today's chum is Ian Stone, engineer turned comedian.