This instrument is based on patent #975,682, granted to Philip Ferber in 1910 and assigned to Keuffel & Esser. According to the patent, Ferber intended "to combine in one readily portable instrument facilities for measuring distances, ascertaining vertical angles and slopes and taking compass bearings, the combined angle, grade and stadia readings being read simultaneously in the same field of view."
The instrument consists of an achromatic terrestrial telescope with cross and stadia hairs, and a circular box that serves as either a magnetic compass or a clinometer. Keuffel & Esser proclaimed that the Stadia hand Transit "gives more accurate results than any similar portable instruments, and gives them in less time," and they were still offering it in the 1930s. This example belonged to the University of Montana. The inscriptions read “KEUFFEL & ESSER Co NEW YORK" and "Pat. Nov. 15, 10.”
Ref: Keuffel & Esser, Catalogue (New York, 1913), p. 425.
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