Cambridge University Library holds the largest and most important collection of the scientific works of Isaac Newton (1642-1727). More than 4,000 pages have been scanned, including his annotated copy of Principia Mathematica, containing Newton's laws of motion and gravity.
This site contains Darwin's complete publications and many of his handwritten manuscripts. There are over 50,000 searchable text pages and 40,000 images. There is also the largest Darwin bibliography and the largest manuscript catalogue ever published