Five Discoveries That Were Proven, Then Lost. How Did We Get Them Back?

Five discoveries were written down, tested, and shown to work, and then lost anyway. This episode asks how that happens, and what it took to get each one back. Covered in this episode: The Archimedes Palimpsest. A tenth century copy of Archimedes erased and overwritten as a prayer book finished in 1229, lost again after 1908, and read back over twelve years with multispectral imaging and x-rays at the Walters Art Museum. Roman concrete. Why MIT researchers argue that the white lime clasts once dismissed as sloppy mixing gave Roman concrete a self-healing capability. James Lind and scurvy. A 1747 shipboard trial in which only the citrus pair recovered, a 1795 lemon juice order, the 1804 switch to lime juice, and scurvy on the British Arctic Expedition of 1875 and 1876. Ignaz Semmelweis. An 1847 handwashing order in Vienna, a dramatic fall in mortality, and a result accepted only after his lifetime. Gregor Mendel. Pea experiments read to a society in 1865 and rediscovered independently by three botanists in 1900. This is a history episode, not medical advice. New episodes every two weeks. Sources (each claim checked against these pages on 2026-09-23): Walters Art Museum, Lost and Found: The Secrets of Archimedes: https://thewalters.org/news/lost-and-... The Archimedes Palimpsest project, History of the Archimedes Manuscript: https://www.archimedespalimpsest.org/... MIT News (2023-01-06): https://news.mit.edu/2023/roman-concr... James Lind Library, Lind J (1753): https://www.jameslindlibrary.org/lind... Naval History magazine (U.S. Naval Institute), Finding the Cure for Scurvy: https://www.usni.org/magazines/naval-... Scott Polar Research Institute, Freeze Frame: British Arctic Expedition 1875-6: https://www.freezeframe.ac.uk/resourc... Science History Institute, Ignaz Semmelweis: https://www.sciencehistory.org/educat... Eurosurveillance (Pittet D, Allegranzi B, 2018), PMC6053623: https://pmc.ncbi.nlm.nih.gov/articles... Cureus (2024), Pioneering Hand Hygiene: Ignaz Semmelweis and the Fight Against Puerperal Fever: https://pmc.ncbi.nlm.nih.gov/articles... National Human Genome Research Institute, Online Education Kit: 1865 Mendel's Peas: https://www.genome.gov/25520230/onlin... National Human Genome Research Institute, Online Education Kit: 1900 Rediscovery of Mendel's Work: https://www.genome.gov/25520238/onlin...