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
Double image dynameter micrometer, by George Dollond, London, England, 1820-1852. Double image micrometer in case 1820-1852
Double image dynameter micrometer in fitted red leather covered wooden case, by George Dollond, London, England, 1820-1852. Double image micrometer in case 1820-1852