The incident occurred in the mid-1660s, when Isaac Newton retreated to his family home in northern England after an outbreak of the plague closed the University of Cambridge, where he had been studying.

An 18th-century account of how a falling piece of fruit helped Isaac Newton develop the theory of gravity is being posted to the Web, making scans of the fragile paper manuscript widely available to the public for the first time.

Newton's encounter with an apple ranks among science's most celebrated anecdotes, and Britain's Royal Society said it was making the documents available online Monday.