Paul David and Peter Lindert made extensive, and very useful, comments on earlier versions of this article. Martha Shiells and Robert Evanson, the discussants of the paper at the Economic History Association meetings, also made valuable criticisms. I am grateful for helpful suggestions on earlier drafts from Ester Boserup, Lance Davis, Akhil Gupta, Stanley Engerman, Robert Gailman, Joan Hannon, Larry Neal, Bill Parker, Paul Rhode, Peter Solar, Bill Sundstrom, Ben Ward, and Gavin Wright.Google Scholar

¹ See Bairoch, Paul, “Agriculture and the Industrial Revolution, 1700–1914,” in Cipolla, Carlo, ed. The Fontana Economic History of Europe (New York, 1976), vol. 3, p. 472.Google Scholar

² Jacob, William, Tracts Relating to the Corn Trade and Corn Laws: including the Second Report (London, 1828), First Report, pp. 96–99.Google Scholar

³ Blum, Jerome, Noble Landowners and Agriculture in Austria, 1815–1848 (Baltimore, 1948), pp.167–70.Google Scholar

⁴ U.S. Bureau of the Census, Historical Statistics of the United States (Washington, D.C., 1976), Part 1, pp. 24–37, 460. The Northeast comprises New England, New York, New Jersey, and Pennsylvania.Google Scholar

⁵ The wheat yield per acre in the northeastern United States in the 1840s was about 16 bushelsper acre, and the oats yield about 28 bushels per acre. See Parker, William N. and Klein, Judith L. V., “Productivity in Grain Production in the United States 1840–60 and 1900–10,” in National Bureau of Economic Research, Output, Employment and Productivity in the United States After 1800, Studies in Income and Wealth, 30 (New York, 1966), pp. 548–52.Google Scholar

⁶ See Clark, Gregory, “The Agricultural Revolution in Britain, 1661–1841: Changes in People versus Changes in Technique” (unpublished manuscript, Stanford University, 1987).Google Scholar

⁷ Kosminsky, E. A., Studies in the Agrarian Histoiy of England in the 13th Century (New York, 1956) pp. 100, 216, 223.Google Scholar

⁸ Hallam, H. E., “Population Densities in Medieval Fenland,” Economic History Review, 2nd ser., 14 (1961).CrossRefGoogle Scholar

⁹ Such yields are given in Titow, J. Z., Winchester Yields: A Study in Medieval Agriculture Productivity (Cambridge, 1972).Google Scholar

¹⁰ Bidwell, Percy W. and Falconer, John I., History of Agriculture in the Northern United States,1620–1860 (Washington, D.C., 1925), pp. 205–6;Google ScholarU.S. Department of Labor, Thirteenth Annual Repor of the Commissioner of Labor (Washington, D.C., 1899), vol. 2, pp. 433–73.Google Scholar

¹¹ Gardener's Chronicle and Agricultural Gazette, 27 Apr. 1850, pp. 266–67.Google Scholar

¹² Jacob, Tracts, First Report, pp. 19, 96–99, 132–35.Google Scholar

¹³ The annual wages of ploughmen on a number of manors can be calculated from Rogers, James E. Thorold, A History of Agriculture and Prices in England (Oxford, 1866), vol. 1, pp. 245, 288–89, vol. 2, pp. 329–34.Google Scholar

¹⁴ Bidwell and Falconer, History of Agriculture, p. 33.Google Scholar

¹⁵ Jacob, Tracts, First Report, pp. 32, 37. Jacob reports that the crown lands had about 8 million acres of mainly arabIc farmland, and one-quarter of the population of the kingdom.Google Scholar

¹⁶ Ibid., pp. 14, 20, 32–33, 36, 97, 133–37.

¹⁷ The total burden on the land in Poland in the 1820s consisted of three elements; about $0.24 of rent per acre, $0.06 of taxes, and the tithe of one-tenth or less of gross output (Jacob, Tracts, First Report, pp. 32–36, 99). Output per acre of tillage land in one large lordship in Poland was about $2.68 of grain, plus an unspecified value of fodder in the straw and fallow grazing. Assuming conservatively that the fodder was worth a quarter of the grain, the value of output per acre was $3.35 (Jacob, Tracts, First Report, pp. 97–99). Thus the total burden on the land was only about $0.64.Google Scholar

¹⁸ The rental value for the United States is derived by taking 4 percent of the value per acre recorded in the 1850 census (U.S. Bureau of the Census, Historical Statistics, pp. 460–62).Google Scholar

¹⁹ If Polish rents were reduced to American levels, the residual per acre left to pay wages would increase by about 27 percent. Combining this with 22 percent more acres of land tilled per worker gives the maximum possible increase in wages with greater land availability as 54 percent.Google Scholar

²⁰ Papadakis, J., Soils of the World (Amsterdam, 1969), classifies most of the soils in the northeastern United States as naturally acid and infertile podsols. British soils are also principally infertile podsols.Google Scholar

²¹ I am grateful to Ester Boserup for this important observation.Google Scholar

²² Hall, A. D., The Book of the Rothamsted Experiments (London, 1919), pp. 35, 55, 63, 72, 84,93.Google Scholar

²³ Hall, Rothamsted Experiments, p. 55.Google Scholar

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²⁵ Thaer, Albert, The Principles of Agriculture (London, 1844), vol. 2, p. 407;Google ScholarMcCulloch, J. R., A Statistical Account of the British Empire (2nd edn., London, 1839), p. 466.Google Scholar

²⁶ This figure assumes the reaper cuts a three-foot-wide swath through the grain.Google Scholar

²⁷ Jacob, Tracts, Second Report, p. 89.Google Scholar

²⁸ Washington, George, Letters to Arthur Young and John Sinclair (Alexandria, 1803), p. 75.Google Scholar

²⁹ Markham, Gervase, Markham's Farewel to Husbandry (14th edn., London, 1683), p. 113.Google Scholar

³⁰ Kershaw, Ian, Boiron Priory: The Economy of a Northern Monastery, 1286–1325 (Oxford,1973), pp. 38, 50.Google Scholar

³¹ Morton, J. C., A Cyclopedia of Agriculture (Edinburgh, 1855), vol. 2, p. 1144.Google Scholar

³² Stephens, Book of the Farm, vol. 2, pp. 335–37; Morton, Cyclopedia, vol. 2, p. 1145.Google Scholar

³³ Thaer, Principles, vol. 1, p. 102.Google Scholar

³⁴ Private communication from Aktil Gupta.Google Scholar

³⁵ Howlett, John, “The Different Quantity and Expense of Agricultural Labour in Different Years,” Annals of Agriculture, 18 (1792), p. 570.Google Scholar

³⁶ Jacob, Tracts, Second Report, p. 29.Google Scholar

³⁷ Jacob, Tracts, First Report, p. 28. It is not entirely clear whether Jacob is discussing free or serf labor.Google Scholar

³⁸ Jacob, Tracts, Second Report, p. 18.Google Scholar

³⁹ Boys, John, A General View of the Agriculture of the County of Kent (London, 1796), p. 59.Google Scholar

⁴⁰ Thaer, Principles, vol. 2, p. 386.Google Scholar

⁴¹ This figure is for manors whose labor accounts are recorded in Rogers, James E. Thorold, A History of Agriculture and Prices in England (Oxford, 1866), vol. 1, pp. 245, 288–89; vol. 2, pp. 273–310, 329–34.Google Scholar Similar data for Ramsey Abbey and Crowland Abbey show threshing rates of 2.37 bushels, and 2.74 bushels per day, prior to 1349. See Page, Frances M., The Estates of Crowland Abbey (Cambridge, 1934);Google Scholar and Raftis, J. Ambrose, The Estates of Ramsey Abbey (Toronto, 1957).Google Scholar

⁴² I use the reaping rate for Podolia as a proxy for that in Poland.Google Scholar

⁴³ Great Britain, Parliamentary Papers, Sixth Report of the Medical Officer of the Privy Council, Appendix 6: Food of die Lowest Fed Classes, vol. 27, 1864, pp. 216–329.Google Scholar

⁴⁴ Gardener's Chronicle and Agricultural Gazette, 27 Apr. 1850, pp. 266–67, and 30 Apr. 1860, pp. 392–93.Google Scholar

⁴⁵ Elsewhere I calculate that while productivity rose by over 50 percent in British agriculture between 1661 and 1841, the amount of increase that was attributable to technical progress was only about 15 percent, the rest coming from more labor inputs per worker and more intense work. See Clark, “The Agricultural Revolution in Britain.”Google Scholar

⁴⁶ See Clark, Gregory, “Why Isn't the Whole World Developed? Lessons from the Cotton Mills,” this JOURNAL, 45 (Mar. 1987), pp. 141–74.Google Scholar