In 1789, Library Hall became the first library which opened to the public, the predecessor to the Library of Congress. The hall was refurbished during the 1950s and today holds an excess of books from the Philosophical Hall collection. Rare manuscripts of groundbreaking scientific and historic importance are on hand. The original journals of the Lewis and Clark expedition, and first editions of Sir Isaac Newton's Principia and Charles Darwin's Origin of Species are exhibited. The Declaration of Independence in Jefferson's own handwriting is here.