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Very nice old graphometer brass. Epque XIX.
In his juice.
* Graphometer: The graphometer is an ancient instrument of angular measurement. Mounted on ball, it can "take" the angles between objects in the same plane. It is an instrument of geodesy and topography.
It was invented by Philippe Danfrie, the elder rather than the young, in 1597, if one believes the letters patent made by Henry IV in 1606 and testament1. This semicircle with alidades finlets and will be widely used for over 150 years. He will succeed the graphometer glasses, to 17,602 years.
