Ramsden's mother-of-pearl dynameter, as made by Troughton & Simms, about 1850 Ramsden's mother-of-pearl dynameter 1850
Dynameter micrometer, Ramsden type, with mother-of-pearl line scales and eyepiece fitted with sliding cover, unsigned, English, 1785-1790. Ramsden type dynameter micrometer 1785-1795
Brass dynameter with dial in velvet-lined burgandy leather box with handwriten note, Troughton & Simms, London, 1790-1890 Brass dynameter with dial in velvet-lined burgundy leather box 1790-1890
Split-lens eyepiece position micrometer with spherical crystal micrometer and eyepiece dynameter, all by George Dollond, London in fitted mahogany box, 1820-1830. Split-lens eyepiece position micrometer with spherical crystal micrometer and eyepiece dynameter 1820-1830