The electric lamp was originally patented on January 27, 1880. After a 40 hour "life" test of this lamp using a carbonized cotton thread filament, Edison proclaimed success at his Menlo Park, New Jersey Laboratory on October 21, 1877.
Each 16x20 copy is available at the Edison & Ford Winter Estates 2350 McGregor Blvd, Fort Myers FL 33901. (239) 334 7419. Open from 9 am to 5:30 pm daily.