In the Zone

September 6, 2011 | by Nathaniel Popkin


Image Credit: Dr. Richard Alan Keen

“The summer climate of Philadelphia, and other large cities similarly situated, is an artificial torrid zone, in which the thermometer rises from four to six degrees higher as it does at a distance of a few miles in the country.”

This was Charles Caldwell, a physician, in 1801.

Caldwell was trying to understand why Yellow Fever, a tropical disease, kept recurring in Philadelphia in the 1790s. The chief contributors to Philadelphia’s “factitious climate,” according to Caldwell: deforestation, overbuilding, fuel use, and pavement.

Sound familiar?


About the Author

Nathaniel Popkin Nathaniel Popkin is co-founder of the Hidden City Daily and author of three books of non-fiction, including Philadelphia: Finding the Hidden City (with Peter Woodall and Joseph E.B. Elliott) and two novels, Everything is Borrowed and Lion and Leopard. He is co-editor of Who Will Speak for America, an anthology forthcoming in June 2018, and the senior writer of the film documentary "Philadelphia: The Great Experiment."

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