 He had his information from Newton's favourite niece Catherine Barton, who married John Conduitt, a fellow of the Royal Society, and one of Newton's intimate friends.How much truth there is in what is a plausible and a favourite story can never be known, but it is certain that tradition marked a tree as that from which the apple fell, until 1866, when, owing to decay, the tree was cut down and its wood carefully preserved.Johannes Kepler had proved by an elaborate series of measurements that


The fact that heavy bodies have always a tendency to fall to the Earth, no matter at what height they are placed above the Earth's surface, seems to have led Newton to conjecture that the same tendency to fall to the Earth might have been the cause by which the Moon was retained in its orbit around the Earth.