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Keywords from Image Description:
Snellius baseline r. en Triangulation baseline between Leyden and Zoeterwoude The Netherlands figure from page of Eratosthenes Batavus by Snellius baseline tc highlighted in red Eratosthenes Batavus Snellius derived from file Snellius baseline bw Custom marker Hans Erren Uploaded with Willebrord Snellius Triangulation