The name is absent

Each state estimate was then determined by summing the average hours of direct sunlight
for each county (at its centroid), weighted by the proportion of the county’s total land
area (in square miles) to the state’s total land area (in square miles). While this index is a
rough approximation for historical insolation, it provides sufficient detail to capture state
latitudinal insolation variation and consequently, vitamin D production. Predictably,
Southern states have greater insolation than Northern states. For example, Texas receives
1.43, or 29 percent, more hours of direct sunlight per day than New York. It is also
difficult to interpret insolation’s net direct effect on human health, because greater
insolation reduces calories required to maintain body temperature and produces more
vitamin D, but greater insolation also warms surface temperatures, which may have made
disease environments less healthy from water-borne diseases, especially in the South
(Steckel, 1992, p. 501).

Military Records

All historical height data have various biases. Data used to study 19^th century
white military statures is drawn from the Union Army Recruits in White Regiments
books archived at the University of Chicago’s Center for Population Economics. ⁴ The
White Regiment records were first gathered by collecting a sample of early 19^th century
males mustered into the Union Army between 1861 and 1865. A list of over 20,000
companies was then extracted. A target sample of approximately 40,000 individuals was
decided upon, and 331 companies were selected, producing an initial sample size of
39,616 soldiers. After eliminating immigrants and soldiers born before 1800 and after
1849, there are 24,820 white native military recruits available from these white regiment

⁴Union Army Recruits in White Regiment data is accessed at http://www.cpe.uchicago.edu/data/data.html.

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