Image: The ship Galilee at anchor.

Simon Thode, Ph.D. student in Johns Hopkins University’s History of Science, Medicine, and Technology program, delivered Wednesday’s DTM seminar entitled, “Science at Sea: The Department of Terrestrial Magnetism Pacific Ocean Survey and the Ship as Magnetic Observatory.” Thode’s research interests focus on the shift in the late nineteenth and early twentieth centuries from scientific fieldwork towards experimental science conducted in the laboratory through the lens of physics. Aiming to problematize this narrative, Thode has concentrated on the work of Louis Bauer who led DTM’s magnetic surveys of the Pacific Ocean from the 1890s to the 1920s. Thode argues that although the global magnetic survey can be seen as a reaction to the reductionism of working solely in a laboratory, it is rather part of an older effort to bring the science of fixed locations into the field.

Image: Crew of the Galilee, 1907

Along with many photos of the ships and crew of the Galilee and Carnegie that were utilized in the ocean surveys, Thode offered various insights into day-to-day life aboard both vessels that he had garnered from letters and journals. The ocean surveys required a ship fabricated from a minimum of magnetic materials that could interfere with measurements. Before undertaking the construction of a special ship, Bauer obtained the Galilee, a wooden vessel that had as much iron removed from it as possible. During early cruises of the ship, the scientific crew was able to learn the corrections that had to be applied to raw data as a result of the iron that remained in its construction.

Image: Observers in the observation dome on the Carnegie

Following the Galilee’s final cruise in 1908, the trustees of the Carnegie Institution allowed for the construction of a non-magnetic vessel, named Carnegie, that was similar in size to the Galilee but contained significant differences beyond its lack of magnetism. A notable one was the replacement of the Galilee’s open observation deck by two observatories with glass revolving domes that allowed for more controlled conditions for observers. The magnetic surveys were considered very successful, covering land and sea, and were well-funded until the 1920s when new leadership of the institution pressured Bauer to focus more on laboratory science and less on survey work.

For more information and photos of DTM’s magnetic survey expeditions, click here.