1873 Thermal Map of North America, Delineating the Isothermal Zodiac, the Isothermal Axis of Intensity, and its Expansions up and down the Plateau
DESCRIPTION
An extraordinary thematic map of North America illustrating William Gilpin's ambitious attempt to explain the continent's climate and identify the broad temperate zone he believed destined to support its greatest concentration of population and civilization.
Published in 1873, the map extends from the Arctic to Central America, combining conventional nineteenth century geography with Gilpin's distinctive climatic theories. Two enormous red curves define what he termed the “Isothermal Zodiac” and the “Isothermal Axis of Intensity,” while blue and reddish coloring distinguishes broad climatic regions across the continent.
Mapping Climate and Settlement
Gilpin believed climate, elevation, and geography exerted a powerful influence over human settlement. His “Isothermal Zodiac” represented a broad temperate belt that he regarded as particularly favorable to agriculture, population growth, and economic development, while the circular “Axis of Intensity” emphasized the continental interior. The underlying map provides remarkable geographic detail, extending across the United States, Canada, Mexico, Alaska, the Arctic archipelago, and Greenland. The result is simultaneously a physical map and an argument about where Gilpin believed North America's future population and economic power would develop.
The map also illustrates the optimistic environmental theories that accompanied nineteenth century western expansion. Gilpin believed settlement and cultivation could improve the climate of the arid West, ideas related to the later popularized belief that increased settlement and agriculture could encourage rainfall. Although much of this climatology was eventually disproven, the map provides a fascinating record of how geography and environmental theory were employed to encourage settlement of the continental interior.
William Gilpin and His Vision of the West
The map is closely associated with William Gilpin (1813–1894), Colorado Territory's first governor and one of the nineteenth century's most enthusiastic advocates for the settlement and development of the American West. Gilpin viewed the Rocky Mountains not simply as an obstacle to migration but as the geographic backbone of a future continental nation. His ideas combined geography with an expansive vision of Manifest Destiny, agriculture, population growth, and especially transcontinental railroads that would connect the interior with the rest of the country. Published as one of six maps accompanying his Mission of the North American People, this remarkable sheet transforms physical geography into a visual argument for Gilpin's ambitious vision of America's continental future.
CONDITION
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