This map, made with data from the 1870 census, shows rates of wealth per capita in the settled United States. The scale stretches from white—“under $175 per capita”—to dark orange—“$ ...

This map comes from Francis Amasa Walker’s 1874 Statistical Atlas of the United States, an early exercise in data visualization which was compiled using findings from the 1870 census.

In the 19th century, however, malaria was extremely common within the United States, with over 1 million cases reported during the Civil War alone. The map below depicts deaths from malaria in 1870—10 ...