The popular press then seized on the simple geometric imagery of the map, often without pretending to present cartographic or observational data. This hybrid geographic-astronomical icon thus became a primary way of communicating knowledge and spurring the development of knowledge about Mars.

Additionally, iconic cartographic images played a critical role in the development of scientific and popular knowledge about the supposed cultural geography of Mars. Proper maps, made by mathematically projecting data onto the page, could be produced only by scientists. The cartographic icons they spawned, however, were easily communicable to broad popular audiences. This created a situation in which scholars from outside the discipline of astronomy, as well as non-scientists like commentators and fiction writers, were able to weigh in on the discussion in influential ways. Mainstream astronomers were usually hesitant to comment on speculative elements of the Mars mania, but the fact that it existed had significant effects on funding opportunities for astronomers in an era that was still dominated by private donations and wealthy benefactors rather than government-funded institutions. And the fact that a Mars mania existed at all was primarily, I argue, due to the prevalence of widespread and iconic imagery of the Martian landscape.

Maria Lane is an Assistant Professor in the Department of Geography and Environmental Studies at the University of New Mexico. She has conducted archival research on the history of Mars science at libraries and observatories throughout Europe and North America. She is the author of Geographies of Mars: Seeing and Knowing the Red Planet (University of Chicago Press, 2011).