In honor of the anniversary of Alexander Graham Bell’s first successful telephone call, The Atlantic has an awesome slideshow of some of the best images from his lab notebooks, which have been loving preserved by the Library of Congress. While it’s almost impossible to make out his handwriting, his illustrations of scientific principles and crazy invention ideas are like miniature works of art. The one above is believed to be the first sketch of his telephone system, which was originally only intended as an improvement on the existing telegraph. Science!