Saxony’s Role in the Measurement of the Central European Meridian Arc as an International Geodetic Project Since 1862

Abstract

In 1861 the Prussian officer, Johann Jacob Baeyer, in his memorandum “Ueber die Größe und Figur der Erde”, developed a vision for the measurement of a meridian arc in central Europe. According to him, such a measurement would contribute to the existing knowledge of the dimensions of the earth. Although Prussia and Saxony had been arch enemies for centuries, the Saxon State Ministry decided as early as 1862 that they would take part in the measurement. At this time there existed a relatively accurate triangulation of Saxony which had been completed by Friedrich Ludwig Aster between 1780 and 1825. Although this survey formed the basis for the well-known Saxon topographic maps called Meilenblätter (mile sheets), the relevant triangulation points had not been marked permanently and could therefore not be verified or used for re-measurements. By 1862 the responsible parties realised that the meridian arc measurement could also be used as a basis for exact triangulation, which meant that it would be possible to also use it for better topographic map material (Messtischblätter/Ordnance survey map). The central European project—the first scientific cooperation within Europe—quickly developed an international dimension which can be regarded as the predecessor of today’s International Association of Geodesy (IAG). It was also one of the first projects of international cooperation in the field of surveying. Christian August Nagel, one of the Saxon protagonist’s and the person responsible for the measurements of both the meridian arc and of the triangulation, was a member of the Commission for International Meridian Arc Measurement. This meant that Saxony’s participation in the project was, right from the beginning, integrated in an international context. To honour this agreement, the year 2012 which marks the 150th anniversary of the beginning of the central European meridian arc measurement, has been celebrated in Saxony with an exhibition and a conference.