Berger introduced this instrument in the early 1950s, describing it as a
"modern, practical and sturdy instrument, precision engineered for the
requirements of the contractor and builder." This example was owned by
Charles H. Rutter, a contractor and builder in southern Prince George’s
County, Maryland. Its horizontal circle and vertical arc are divided to single
degrees, and read by verniers to 5 minutes.
Ref: C. L. Berger & Sons, Inc., Solar Ephemeris and Polar Tables
(Boston, 1954), p. 62.