The first electrocardiograph was invented in 1895. That device looked a lot different from today’s machines, and there are some other contenders for the title of “first.”

Research:

• AlGhatrif, Majd, and Joseph Lindsay. “A brief review: history to understand fundamentals of electrocardiography.” Journal of community hospital internal medicine perspectives vol. 2,1 10.3402/jchimp.v2i1.14383. 30 Apr. 2012, doi:10.3402/jchimp.v2i1.14383
• Baldassarre, Antonio et al. “The Role of Electrocardiography in Occupational Medicine, from Einthoven's Invention to the Digital Era of Wearable Devices.” International journal of environmental research and public health vol. 17,14 4975. 10 Jul. 2020, doi:10.3390/ijerph17144975
• Browne, Sir Thomas. “Chap. IV: Of Bodies Electrical.” From Pseudodoxia Epidemica. 1672. https://penelope.uchicago.edu/pseudodoxia/pseudo24.html
• Case Western Reserve. “Cambridge Electrocardiograph, 1920.” https://artsci.case.edu/dittrick/online-exhibits/explore-the-artifacts/cambridge-electrocardiograph-1920/
• Fisch, Charles. “Centennial of the string galvanometer and the electrocardiogram.” Journal of the American College of Cardiology. Volume 36, Issue 6, 15 November 2000. https://www.sciencedirect.com/science/article/pii/S0735109700009761
• Friedman, Paul A. “The Electrocardiogram at 100 Years: History and Future.” Circulation. Volume 149, Number 6. https://doi.org/10.1161/CIRCULATIONAHA.123.065489.
• Fye, W. Bruce. “A History of the Origin, Evolution and Impact of Electrocardiography.” The American Journal of Cardiology. Vol. 73, No. 13. 5/15/1994.
• Goodrich, Joanna. “Forget Electrodes, the First EKG Machine Used Buckets of Saline Solution and Telephone Wire.” IEEE Spectrum. 1/5/2021. https://spectrum.ieee.org/forget-electrodes-the-first-ekg-machine-used-buckets-of-saline-solution-and-telephone-wire
• Howell, Joel D. “Early Perceptions of the Electrocardiogram: From Arrythmia to Infarction.” Bulletin of the History of Medicine, SPRING 1984, Vol. 58, No. 1. Via JSTOR. https://www.jstor.org/stable/44441681
• Jenkens, Dean and Dr Stephen Gerred. “A (not so) brief history of electrocardiography.” ECG Library. 2009. https://ecglibrary.com/ecghist.html
• Macfarlane PW, Kennedy J. Automated ECG Interpretation—A Brief History from High Expectations to Deepest Networks. Hearts. 2021; 2(4):433-448. https://doi.org/10.3390/hearts2040034
• Rautaharju, Pentti M. “Eyewitness to history: Landmarks in the development of computerized electrocardiography.” Journal of Electrocardiology 49 (2016) 1 – 6.
• Rivera-Ruiz, Moises et al. “Einthoven's string galvanometer: the first electrocardiograph.” Texas Heart Institute journal vol. 35,2 (2008): 174-8.
• Salam, Amar M. “The Invention of Electrocardiography Machine.” HeartViews. 2019 Nov 14;20(4):181–183. doi: 10.4103/HEARTVIEWS.HEARTVIEWS_102_19.
• Vincent, Rony. “From a laboratory to the wearables: a review on history and evolution of electrocardiogram.” Iberoamerican Journal of Medicine, vol. 4, núm. 4, pp. 248-255, 2022. https://www.redalyc.org/journal/6920/692072548011/html/

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This 2020 episode covers one of the transitional events between the Black Death and the Renaissance. Wat Tyler’s Rebellion was also known as the Uprising of 1381 or the Great Rising.

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Holly and Tracy talk about Tracy growing up in a mostly Protestant community with little exposure to Catholicism. They also talk about the Gorsuch family's ties to John Wilkes Booth.

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The Christiana Incident offers a snapshot of the U.S. when the country was sorting into states where slavery was upheld and states that had abolished it, and what racist tension looked like at border states in the mid-1850s.

Research:

• “The Christiana Affair Again.” New York Times. Sept. 20, 1851. https://timesmachine.nytimes.com/timesmachine/1851/09/20/87821677.pdf?pdf_redirect=true&ip=0
• “Christiana Resistance 1851.” Christiana Historical Society. https://www.christianahistoricalsociety.com/christiana-resistance
• “The Christiana Trials.” New York Times. Nov. 4, 1851. https://timesmachine.nytimes.com/timesmachine/1851/11/04/87823549.pdf?pdf_redirect=true&ip=0
• The Editors of Encyclopaedia Britannica. "Fugitive Slave Acts". Encyclopedia Britannica, 28 Feb. 2025, https://www.britannica.com/event/Fugitive-Slave-Acts
• “Fatal Fugitive Slave Riot.” Boston Evening Transcript. Sept. 12, 1851. https://www.newspapers.com/image/734734274/
• Forbes, David R. “A True Story of the Christiana Riot.” The Sun Printing House. Quarryville, PA. 1898. https://babel.hathitrust.org/cgi/pt?id=hvd.32044018986661&view=1up&seq=7
• “Fugitive Slave Act 1850.” Yale Law School. Lillian Goldman Law Library. https://avalon.law.yale.edu/19th_century/fugitive.asp
• “Fugitive Slave Riot in Lancaster Co., Pa.” New York Times. Sept. 18, 1851. https://timesmachine.nytimes.com/timesmachine/1851/09/18/109920970.pdf?pdf_redirect=true&ip=0
• “Christiana Riot Trial.” Encyclopedia of Greater Philadelphia. 2015. https://philadelphiaencyclopedia.org/essays/christiana-riot-trial/#national-history-day
• Parker, William. “A Freedman’s Story. The Atlantic. 1866. https://www.christianahistoricalsociety.com/_files/ugd/f64fcb_e6cde1713eb34263af1f191b3f349e21.pdf
• “Who was William Parker?” Christiana Historical Society. https://www.christianahistoricalsociety.com/william-parker

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Pope Leo XIII sought to find a way forward for the Catholic church at a time when the world was rapidly changing and the church was often at odds with those changes.

Research:

• Aubert, Roger-François-Marie. "Leo XIII". Encyclopedia Britannica, 18 May. 2025, https://www.britannica.com/biography/Leo-XIII
• “ELECTION OF POPE LEO XIII.” New York Times. Feb. 21, 1878. https://timesmachine.nytimes.com/timesmachine/1878/02/21/issue.html
• Jedin, Hubert and John Patrick Dolan. “History of the Church: The Church in the Industrial age.” Burns & Oates. 1981. https://books.google.com/books?id=h5LYAAAAMAAJ&source=gbs_navlinks_s
• Masci, David. “A look at popes and their encyclicals.” Pew Research Center. June 9, 2015. https://www.pewresearch.org/short-reads/2015/06/09/a-look-at-popes-and-their-encyclicals/
• Miller, James Martin. “The life of Pope Leo XIII : containing a full and authentic account of the illustrious pontiff's life and work.” G.H. Harr. Omaha, Nebraska. 1908. Accessed online: https://archive.org/details/lifeofleo1300milluoft/page/n5/mode/2up
• O’Reilly, Bernard. “Life of Leo XIII, from an authentic memoir furnished by his order.” Sampson Low, Marston & Co. London. 1903. https://archive.org/details/lifeofleoxiiifro0000orei/page/n9/mode/2up
• Pope Leo XIII. “AETERNI PATRIS.” 1879. https://www.vatican.va/content/leo-xiii/en/encyclicals/documents/hf_l-xiii_enc_04081879_aeterni-patris.html
• Pope Leo XIII. “INSCRUTABILI DEI CONSILIO.” 1878. https://www.vatican.va/content/leo-xiii/en/encyclicals/documents/hf_l-xiii_enc_21041878_inscrutabili-dei-consilio.html
• Pope Leo XIII. “RERUM NOVARUM.” https://www.vatican.va/content/leo-xiii/en/encyclicals/documents/hf_l-xiii_enc_15051891_rerum-novarum.html
• Pope Leo XIII. “Testem Benevolentiae Nostrae.” 1899. https://www.papalencyclicals.net/leo13/l13teste.htm
• “Religious.” Chicago Tribune. February 24, 1878. https://www.newspapers.com/image/349728621/?match=1&terms=Pope%20Leo%20XIII
• “Vatican country profile.” BBC. Nov. 17, 2023. https://www.bbc.com/news/world-europe-17994868

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This 2022 episode covers Griswold v. Connecticut, the U.S. supreme court decision that overturned laws banning contraception – at least, for married couples.

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Tracy talks about her experiences with the Blue Ridge Parkway growing up, including her mixed feelings about it. Holly talks about the theft of the Mona Lisa.

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The Blue Ridge Parkway is the longest roadway in the U.S. that was planned as a single unit. Its origin is connected to government efforts to provide relief from the Great Depression, and conservation of the Blue Ridge Mountains.

Research:

• "Restoring Western North Carolina's Infrastructure: NCDOT Receives $250 Million in Federal Emergency Relief Funds." National Law Review, 21 Feb. 2025. Gale Academic OneFile, link.gale.com/apps/doc/A828346450/GPS?u=mlin_n_melpub&sid=bookmark-GPS&xid=b22cedc8. Accessed 12 May 2025.
• "The Blue Ridge Parkway." NCpedia. Accessed on May 14th, 2025. https://www.ncpedia.org/anchor/blue-ridge-parkway.
• “Report In Full of Secretary Work’s Appalachian National Park Committee. “National Parks and Conservation Magazine.” 1924-11-25: Iss 42. https://archive.org/details/sim_national-parks_1924-11-25_42/page/n5/
• Averill, Graham. “The Blue Ridge Parkway: A Monumental Drive.” Our State. 9/27/2021. https://www.ourstate.com/the-blue-ridge-parkway-a-monumental-drive/
• Buxton, Barry. “Blue Ridge Parkway: Agent of Transition.” Proceedings of the Blue Ridge Parkway Golden Anniversary Conference. Appalachian Consortium Press/Boone, North Carolina. 1986.
• Coutant, Linda. “Helene Recovery, 7 Months After the Storm.” National Parks Conservation Association. 4/26/2025. https://www.npca.org/articles/8198-helene-recovery-7-months-after-the-storm
• Coutant, Linda. “Helene: Facing Loss and the Blue Ridge Parkway’s ‘Most Tremendous Challenge’.” National Parks Conservation Association. https://www.npca.org/articles/5459-helene-facing-loss-and-the-blue-ridge-parkway-s-most-tremendous-challenge
• “Driving Through Time: The Digital Blue Ridge Parkway.” https://docsouth.unc.edu/blueridgeparkway/
• Jolley, Harley E., “Blue Ridge Parkway: The First 50 Years,” Appalachian State University Libraries Digital Collections, accessed May 14, 2025, https://omeka.library.appstate.edu/items/show/43667.
• Landis, Mark. “This 5,600-mile highway route was created to see 12 national parks in the West.” The Sun. 6/13/2022. https://www.sbsun.com/2022/06/13/this-5600-mile-highway-route-was-created-to-see-12-national-parks-in-the-west/
• Mitchell, Anne V. “Culture, History, and Development on the Qualla Boundary: The Eastern Cherokees and the Blue Ridge Parkway, 1935-40.” Appalachian Journal , WINTER 1997, Vol. 24, No. 2. Via JSTOR. https://www.jstor.org/stable/40933835
• National Park Service. “Blue Ridge Parkway: Virginia and North Carolina.” From Highways in Harmony online books exhibit. https://www.nps.gov/parkhistory/online_books/hih/blue_ridge/index.htm
• Roberts, Brett G. “Returning the Land: Native Americans and National Parks.” Ave Maria Law Review 148 (Spring, 2023). https://www.avemarialaw.edu/wp-content/uploads/2023/07/v21.Roberts.final38.pdf
• Speer, Jean Haskell. “’Hillbilly Sold Here’: Appalachian Folk Culture and Parkway Tourism.” From Parkways: Past, Present and Future. International Linear Parks Conference. Appalachian State University. (1987). Via JSTOR. https://www.jstor.org/stable/j.ctt1xp3kv8.33
• S. Department of Transportation Federal Highway Administration. “America's Highways 1776-1976.” U.S. Government Printing Office. https://archive.org/details/AmericasHighways1776-1976
• Whisnant, Anne Mitchel. “Routing the Parkway, 1934.” Driving Through Time. DocSouth. https://docsouth.unc.edu/blueridgeparkway/overlooks/competing_routes/#footnote9
• Whisnant, Anne Mitchell. “A Capsule History of the Blue Ridge Parkway.” Appalachian Voice. 10/11/2017. https://appvoices.org/2017/10/11/a-capsule-history-of-the-blue-ridge-parkway/
• Whisnant, Anne Mitchell. “Super-Scenic Motorway: A Blue Ridge Parkway History.” University of North Carolina Press. 2006.
• Zeller, Thomas. “Consuming Landscapes: What We See When We Drive and Why It Matters.” Johns Hopkins University Press. 2022. https://dx.doi.org/10.1353/book.103002

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