The observatory, the land-based ship and the crusades: earth sciences in European context, 1830-50.

The article focuses on scientific observation methods in expeditionary and sedentary contexts to demonstrate how the fields of meteorology and geomagnetism were intimately intertwined. It emphasizes the role of Adolphe Quetelet, the director of the Brussels Observatory in Belgium. It reevaluates the participation of the French scientific community in the German and British geomagnetic explorations, moving beyond the popular story of Arago's opposition to these activities. This paper attempts to contribute to a better historical comprehension of the revival of the earth sciences during the second quarter of the 19th century.