{"id":621792,"date":"2026-01-18T21:04:13","date_gmt":"2026-01-18T20:04:13","guid":{"rendered":"https:\/\/cronologia-universale.it\/1900-6\/"},"modified":"2026-01-18T21:04:13","modified_gmt":"2026-01-18T20:04:13","slug":"october-21-1884","status":"publish","type":"post","link":"https:\/\/cronologia-universale.it\/en\/october-21-1884\/","title":{"rendered":"October 21, 1884"},"content":{"rendered":"<p>Thomas Alva Edison is awarded US Patent 307031 for the thermionic emission indicator (Edison Effect). 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