Description

Described in the 1921 Keuffel and Esser catalogue as an “angle mirror”, this diminutive instrument is actually a fine focussing/vernier controlled miniature sextant.  Arc circle runs out to 100 degrees (90 useable), vernier operates by worm and screw measuring to 1 arc minute, twin mirrors (90% silvering), arc circle and frame are 3 inches in length, hexagonal ebony handle with loop for chain or neck string. Tension on the mirrors is acheived by the spring on the back. Composed of aluminum and black enamelled steel. Signed Keuffel and Esser Co.  New York.  Can be used for simple computations of angles and distances (see photo from the catalogue description) in vertical and horizontal planes. Used by surveyors, civil engineers and the military.Velvet lined Morocco case measures 3 1/2 x 3 1/2 x 1 1/2 inches deep with secure closure. An unusual find.