Prismatic Magnifying Periscope, Mark IX

Prismatic Magnifying Periscope, Mark IX, 1918 by R & J. Beck Ltd., Polished brass tubular periscope. The object prism is let into a flattened section at the top of the one inch diameter tube. The eye piece at the bottom is in a horizontal tubular extension, which screws in and out to focus. One prism fractured. The tube ends in a threaded hole into which a wooden (oak?) handle is screwed. Where the eyepiece joins the main tube is a round disc marked: PERISCOPE, Mk IX, 1918, R & J. BECK Ltd., No. 16130.