Menlo Park, New Jersey, no date (ca. 1880s). Two cabinet card photographs depicting the interior of Edison's lab, showing the testing of numerous lightbulbs. Accompanied by two larger paper reproductions, each inscribed on verso by lab assistant Herbert S. Read: "Lamp testing room in Edison Laboratory where I worked in 1886..." Albumen prints lightly spotted, paper photographs slightly curled, some small closed tears to edges.