Cartoon to celebrate the 300th anniversary of the publication of Isaac Newton's great work, Philosophiae Naturalis Principia Mathematica (Mathematical Principles of Natural Philosophy"), in 1687. Newton (1642-1727) developed the theory of universal gravitation in the book. According to the well-known story, the idea of universal gravitation first came to him when, at the age of 22, he was sitting in the garden of his family home at Woolsthorpe, Lincolnshire, and saw an apple fall to the ground. Newton himself is reported to have told this story to friends in 1726-1727, near the end of his life."