This is a 56 hour instrument with a spring detent escapement, and indications for hours, minutes, seconds, and up and down. It is not in its original box, but rather in one signed "WM. BOND & SON (/) Boston (/) 614." Weston College donated it to the Smithsonian in 1967. In the late 1930s, a chronometer of this sort cost $450.Ref: T. S. & J. D. Negus, Illustrated Catalogue of Nautical Instruments (New York, ca. 1938), pp. 201 and 251.
Marvin E. Whitney, The Ship's Chronometer (Cincinnati, 1985), pp. 341-343.
