When John C. Calhoun, then U.S. Secretary of State and former US Senator from South Carolina, claimed that freedom was bad for blacks, and that the 1840 U.S. Census showed that blacks in the North had high rates of insanity and mortality, Smith responded with a masterful paper. In "A Dissertation on the Influence of Climate on Longevity" (1846), published in "Hunt's Merchants' Magazine", Smith analyzed the census both to refute Calhoun's conclusions and to show the correct way to analyze data. He showed that blacks in the North lived longer than slaves, attended church more, and were achieving scholastically at a rate similar to whites.