If you appreciate 19th-century American science/mechanics ephemera, Scientific American has made accessible for a few weeks its digital archive of Scientific American Weekly (28 Aug 1845 - 25 Dec 1909): http://www.nature.com/scientificamerican/archive/index_1909.html A small heads-up... I came across dozens of unreadable (damaged) pdf- files, missing and misdirecting links, and other organizational flaws that put a slight damper on this "treasure trove". The text is OCR of course so, while a complete issue may be searchable in your pdf- viewer, don't expect too much.