This Lens is inscribed 'Prince's Rapid Hemispherical 808 L. M. Prince & Bro Cincinnati, O.' It was most likely manufactured in the 1880's or 1890's, as Prince began selling a camera (with a different lens) in 1884. The focal length of this lens is not marked, though I measured it at approximately 18 inches. Overall the lens is in remarkably good shape considering it's age, t is a small scratch on the bottom lens (visible in pictures) and some oil has seeped into the edges around the top lens (visible in pictures). This lens would be a great addition to any collection, as well as a nice decorative piece.