1 Conrad, Alfred H. and Meyer, John R., “The Economics of Slavery in the Antebellum South,” in The Reinterpretation of American Economic History, ed. Fogel, Robert W. and Engerman, Stanley L. (New York: Harper & Row, 1971), pp. 95–130; and Sutch, Richard, “The Breeding of Slaves for Sale and the Westward Expansion of Slavery, 1850–1860,”Southern Economic History Project Working Paper No. 10, Institute of Business and Economic Research, University of California, Berkeley,November 1972. Eastern states and Old South are used here synonymously.
2 Passel, Peter and Wright, Gavin, “The Effects of Pre-Civil War Territorial Expansion on the Price of Slaves,” Journal of Political Economy, vol. 80, no. 6 (1972), pp. 1188–202.
3 We are interested here in the expansion's effect on eastern wealth through its impact on product prices and slave movements. We leave as an open question whether large numbers of eastern planters earned significantly higher returns on their own entrepreneurial talents by themselves moving westward. For the purposes of our analysis, then, we shall permit only slaves to move from East to West keeping the other factors of production, land, capital, and white managerial labor, fixed in the East. These three non-slave inputs form a composite input referred to as “land “below. The probable error involved in assuming only slaves moved West seems small. As Fogel and Engerman assert, “On a majority of the large plantations the top nonownership management was black.” See Fogel, Robert W. and Engerman, Stanley L., Time on the Cross, vol. I (Boston, 1974), 212.
4 Indeed the Mississippi Constitution expressly prohibited the importation of slaves for sale from 1833 and 1837. Despite this constitutional prohibition, the Mississippi legislature placed a 2.5 percent tax on the trade during the period, rather than enforce the prohibition. See Syndor, Charles S., Slavery in Mississippi, (American Historical Association, Mass., 1965), pp. 162–68.
5 Note that the output supply functions take factor marginal products as parameters, while the slave excess demand and supply curves are developed with output price as a parameter.
6 Strictly speaking this is only correct for a rising price of output; if the price of output falls no exportation will take place. On the other hand, since MPsw > MPsw, slaves would not be shipped back to the East. The supply curves Yes and Yws become perfectly inelastic for a price decline.
7 “Agriculture Census of the United States 1860,” Joseph C. G. Kennedy, Superintendent (Washington: Government Printing Office, 1864), pp. 185–87. This Census gives production by state of tobacco and cotton. Cotton prices were taken from Gray, Lewis Cecil, History of Agriculture in the Southern United States to 1860, vol. II (New York, 1941), 765.
8 The most appropriate mechanism to analyze this issue is a model permitting two distinct outputs with distinct demands in the East, and one output, cotton in the West. Unfortunately lack of empirical information such as the number of exports of slaves from tobacco vs. cotton states precludes this option. Hence we are forced to deal with a composite tobacco-cotton output in the East.
9 Sutch, “Breeding of Slaves,” pp. 42–58.
10 Robert W. Fogel and Stanley L. Engerman, “The Market Evaluation of Human Capital: The Case of Slavery,” unpublished paper presented to the Annual Cliometrics Conference at Madison, Wisconsin, April 27–29, 1972, Charts III and IV.
11 Prior to 1850 slaves were measured in nondecimal age units; in addition the age categories chosen are different for each census. While it remains possible to obtain an aggregate volume of exports, an export age breakdown for those pre-1850 decades is not forthcoming. Nor is it possible to obtain age group survival rates for the entire slave population due to varying classification procedure
12 See Sutch, “Breeding of Slaves,” p. 10, and Fogel and Engerman, Time on the Cross, p. 47.
13 Fogel and Engerman, Time on the Cross, p. 44.