Electromagnetic machine, devised and constructed by the US physicist Joseph Henry (1797-1878). He made it in Albany, New York, in 1831, for the laboratory of Yale College. It was operated with battery cells and used to determine the lifting power of the magnet (upper centre). It could lift between 900 and 1400 kilograms. Weights are used here, but the original apparatus was designed to lift people standing on the platform. This photograph is from a collection of unpublished images, dating from the 1860s to the 1920s, taken for 'The Pageant of America: A Pictorial History of the United States' (1925-1929).