Pocket comparator

A pocket comparator is an optical device for measuring and inspection comprising a loupe and a reticle.

[1] The instrument was developed and manufactured by the Bell & Howell Company, but similar instruments of other names are made by other manufacturers.

[2][3] It is used for: Measurements are performed by bringing the surface of the reticle as close as possible to the work inspected.

[8]

Bell & Howell Pocket Comparator
Reticle of Bell & Howell Pocket Comparator
Typographer Henri Friedlaender at work. Note Pocket Comparator at 01:10.