- Sir Isaac Newton's manuscripts published online by Cambridge University Library
- More than 4,000 pages -- a fraction of university's Newton archive -- digitized so far
- Experts say notes are "some of the most papers and documents in the history of science"
- Newton described law of gravity, developed calculus, studied properties of light
A huge collection of papers belonging to pioneering scientist Sir Isaac Newton -- the father of gravity -- has been posted online by Cambridge University.
The archive includes Newton's college notebooks and some of his most important writings from the 1660s on mathematics and calculus, optics and gravity.
They appear alongside an annotated copy of "Principia Mathematica," the book in which Newton set out his laws of motion and gravity, and which is regarded as one of the world's most significant scientific works.
More than 4,000 pages of Newton material have been digitized so far, with archivists photographing and uploading as many as 200 pages a day.
Grant Young, the library's digitization manager, said the collection contained "perhaps some of the most important papers and documents in the history of science," which would give viewers a valuable insight into Newton's working methods.
"Anyone, wherever they are, can see at the click of a mouse how Newton worked and how he went about developing his theories and experiments," he said.
"Before today, anyone who wanted to see these things had to come to Cambridge. Now we're bringing Cambridge University Library to the world."
Many of the papers -- some of them badly damaged by fire or water -- have undergone delicate conservation work before being added to the archive.
They are also accompanied by transcriptions by the University of Sussex's Newton Project, allowing readers to decipher Newton's handwriting.
But some of the notes added to the papers over the years suggest some of the scientist's contemporaries may not have approved of the online publication.
Several of the manuscripts contain the line "not fit to be printed," written by Thomas Pellet, who was asked to review Newton's work after his death.
The Newton archive is part of Cambridge's Digital Library project that will eventually showcase other important scientific papers, including the works of Charles Darwin, Lord Kelvin and Ernest Rutherford.