JOHN HARRISON, The Principles of Mr. Harrison's Time-keeper, with plates of the same, Published by Order of the Commissioners of Longitude, London; W. Richardson and S. Clark and sold by John Norse and Mess. Mount & Page, 1767, 4to, 9 folding plates (lacking plate 1V) - Alexander Cumming, The elements of Clock and Watch-work, Adapted to Practice. In Two Essays, London, 1766, 4to, 15 folding plates (lacking plate 11).
The two works bound together in one volume, nearly contemporary reversed calf (soiled and rubbed)
267mm. x 205mm.