Stadiometer, by W. Heath, Devonport, Mid-19th Century

Stadiometer made of silvered copper alloy and black leather with a table of distances fixed to the outer barrel. There are two draw-tubes with marks and numbers from 100-200 [probably focal lengths]. At the eye end is a small hole a millimetre in diameter and at the further end is a rectangular graticule, measuring 1.25 x 0.5 inch engraved on a piece of plain glass.