Very rare Carl Zeiss Jena Anastigmatlinse F=224/350mm Triple Convertible Lens, c.1902 (see images for condition).
Triple convertible lens, featuring two optical elements: 1:12.5/224mm No.24782 and 1:25/350mm No.24766
Both lenses are flawless. Not sure if mounting flange original to this lens. Lens threads in, but not completely all the way.