¹ Jacob Schmookler, “Changes in Industry and in the State of Knowledge as Determinants of Inventive Activity,” Proceedings of the Minnesota Conference on Inventive Activity held in. May 1960 (forthcoming); “Economic Sources of Inventive Activity,” The Journal of Economic History, XXII, No. I (March 1962), 1–20.

² North, Douglass C., The Economic Growth of the United States (New Jersey: Prentice-Hall, Inc. 1961), p. 8Google Scholar. For a formal model of innovations see Mansfield, Edwin, “Technical Change and the Rate of Imitation,” Econometrica, XXIX, No. 4 (Oct. 1961), 741–66CrossRefGoogle Scholar

³ Kendrick, John W., Productivity Trends in the United States, National Bureau of Economic Research, General Series, No. 71 (Princeton: Princeton Univ. Press, 1961), pp. 343–57.Google Scholar

⁴ Gallman, Robert E., “Commodity Output, 1839–1899,” Trends in the American Economy in the Nineteenth Century, Studies in Income and Wealth of the National Bureau of Economic Research, Vol. 24 (Princeton: Princeton Univ. Press, 1960), pp. 13–72.Google Scholar

⁵ Towne, Marvin W. and Rasmussen, Wayne D., “Farm Gross Product in the Nineteenth Century,” Trends in the American Economy in the Nineteenth Century, Studies in Income and Wealth of the National Bureau of Economic Research, Vol. 24 (Princeton: Princeton Univ. Press, 1960), pp. 255–316.Google Scholar

⁶ Schmookler, Jacob, Statistics of Patents Classified by Industry, United States, 1837–1957 (University of Minnesota, 1961) Part I (mimeographed).Google Scholar

⁷ Jacob Schmookler, “Economic Sources,” p. 2

⁸ See, for example, Bidwell, P. W. and Falconer, J. I., History of Agriculture in the Northern United States, 1620–1860. (Washington: Carnegie Institution of Washington, 1925)Google Scholar, and Quaintance, H. W., The Influence of Farm Machinery on Production and Labor (University of Wisconsin, 1904), p. 7.Google Scholar

⁹ Towne and Rasmussen, p. 259.

¹⁰ Ruttan, Vernon, “Usher and Schumpeter on Invention, Innovation and Technological Change,” Quarterly Journal of Economics, LXXIII, No. 4 (Nov. 1959), 596–606, 602–3.CrossRefGoogle Scholar

¹¹ The total “pure” agriculture series consists of the following subseries: Earth Preparing and Planting:—Harrows and Diggers; Plows; Planting; and Manure Spreaders. Harvesting:— Fruit Harvesters and Orchard Plows; Harvesters-Cutters; Cutting, Conveying, and Binding; Harvester Motors (excl. corn and cotton); Shockers; Tedders and Rakes; Corn Harvesting, Threshing, Cutting; Hay Handling; Cotton Harvesting, Picking and Chopping Plows; Grain. Harvesting, Threshing, Cutting; Misc. Harvesting; Unearthing Plants. Bee Culture, Livestock and Miscellaneous Agriculture: Bins and Granaries; Bee Culture; Milkers; Misc. Dairy Farm Equipment; Poultry Husbandry Equipment; Animal Housing and Confining; Animal Feeding; Animal Watering; Animal Grooming; Animal Controlling; Misc. Animal Husbandry.

¹² Quaintance, p. 8.

¹³ While it is doubtful as to the analytic value of this observation, it is interesting to note that between 1840–1867 the harvesting series, the earth preparing and planting series, and thus the total series, each has the configuration of a logistic growth curve: a relatively short period of rapid growth. However, unlike the usual growth curve, the smoothed-out series did not continue to fall after its major downturn, which occurred in 1867. Instead, after falling until 1873, the series began a gradual rise which lasted until 1884. It then fell slightly during the next three years.

¹⁴ The fall in agricultural patents between 1861–1864 and the increasing number of patents on firearms and other weapons of warfare issued during these years led Quaintance to conclude that the “minds of inventors as well as of the working classes were given to other matters” than agriculture. Quaintance, p. 8.

¹⁵ Shannon, Fred, The Farmer's Last Frontier (New York: Farrar and Rinehart, Inc., 1945), pp. 126–27 for the depletion of farms, pp. 125–37 for a narrative of inventions.Google Scholar

¹⁶ Bogart, Ernest L. and Kemmerer, Donald L., Economic History of the American People (rev. ed.; New York: Longmans, Green and Company, 1942), p. 312.Google Scholar

¹⁷ Inventions in Four Industries (forthcoming).

¹⁸ Among the inventions that occurred in the pre-harvest category between 1840–1858 were William T. Pennock's grain drill, patented in 1841; Joel Nourse's plow of 1842; Moses and Samuel Pennock's grain drill of 1842; George Page's disk plow of 1847; J. Pierson's adjustable grain dropper of 1848; Pierpont Seymour's one-horse broadcast sowing machine of 1849; N. Foster, Gilbert Jessup, and C. P. and H. L. Brown's force feed grain drill of 1851; E. McCormick's marking device for corn planters of 1855; George Esterley's sulky cultivator, B. C. Hoyt's rotary cultivator plow, and M. Furley's single bottom sulky plow, all of 1856; and M. Robbins' wire check-rower for corn planting of 1857.

Improvements in the harvesting category in this period included Jacob Wemple and George Westinghouse's patent on a combined thresher and fanning-mill in 1843; George Esterley's header of 1844; Alexander Wilson's improved mowing machine of 1846; Joseph Haine's header of 1849; William Watson's corn harvester, Samuel Rembert and Jedediah Prescott's mechanical corn picker, and John Heath's grain binder, all of 1850; William H. Seymour's self-raking device of 1851; Palmer and William's patent on a sweep-rake in 1851; John Cox and Cyrus Roberts' thresher of 1852; George Howe's hand-operated corn picker of 1855; Lewis Miller and Cornelius Aultman's mowing machine of 1856; and W. W. Marsh's reaper, Cyrus H. McCormick's automatic raking device, and Allen Sherwood's mechanical grain binder, all of 1858. With the exception of raking devices and the success of the Marsh reaper, the inventions in the harvesting category do not seem to have had the technological or the commercial importance of the developments that were concurrendy being made in the pre-harvest phase of production.

¹⁹ Faulkner, Harold U., American Economic History (6th ed.; New York: Harper Brothers Publishers, 1947), pp 220, 379Google Scholar.

²⁰ Achinstein, Asher, “Economic Fluctuations,” in American Economic History, edited by Harris, Seymour E. (New York: McGraw-Hill Book Company, Inc., 1961), pp. 162–80Google Scholar.

²¹ Gates, Paul W., The Farmer's Age: Agriculture; The Economic History of the United States, Vol. 3 (New York: Holt, Rinehart and Winston, 1960)Google Scholar; Taylor, George R., The Transportation Revolution, 1815–1860, The Economic History of the United States, Vol. 4 (New York: Rinehart, 1954), pp. 135–36, 346–49Google Scholar; North, Economic Growth, pp. 135 ff.

²² North, Economic Growth, p. 146.

²³ A formal model of the behavior of a utility-maximizing inventor is presented in Jacob, Schmookler and Oswald, Brownlee's “Determinants of Inventive Activity,” American Economic Review, Papers and Proceedings, LII (May 1962), 165–76Google Scholar.

²⁴ Schmookler, Jacob, “The Level of Inventive Activity,” The Review of Economics and Statistics, XXXVI, No. 2 (May 1954), 183–90, 190CrossRefGoogle Scholar.

²⁵ Gates, Farmer's Age, p. 271.

²⁶ Yield per acre rose in corn production from twenty-five bushels in 1800 to 25.9 bushels in 1900 and fell in wheat production from fifteen bushels in 1800 to 13.9 bushels in 1900. Man-hour requirements per acre fell in this period from eighty-six to thirty-eight in corn production and from fifty-six to fifteen in wheat production. Historical Statistics of the United States, Colonial Times to 1957 (Washington, D. C.: U. S. Census Bureau, 1960), series K 83–97, p. 281Google Scholar.

²⁷ In general, a profit-maximizing firm will adopt a process only if it believes that the increase in discounted profits gained from adopting the process will exceed its purchase price. The likelihood of any invention being adopted thus depends upon the capital cost of the invention, the extent, if any, of shifts in the marginal cost and marginal revenue schedules, the discount factor, and the time period over which profits are discounted.

²⁸ For example, assume that a competitive firm, with at least one fixed input and conventionally shaped cost curves, finds itself in an equilibrium position. Then allow product prices to fall while average costs rise because the firm must compete with alternative users of its variable input who are in the process of increasing the price they pay for this input. In order to prevent economic loss and thus being driven from the industry, the firm must make its variable input more efficient, thus shifting its marginal cost curve downward. If it succeeds in doing so it will attain a new equilibrum position at the lower market price for its output by operating on a lower average cost curve and by producing a larger output. But the specter of falling prices, rising costs, and the consequent downward pressure on profits in this industry may have the effect of convincing inventors that this is an unprofitable industry and thus dissuade them from engaging in inventive activity directed towards this industry.

²⁹ Schmookler, “Economic Sources,” p. 2.

³⁰ Lebergott, Stanley, “Wage Trends, 1800–1900,” Trends in the American Economy in the Nineteenth Century, Studies in Income and Wealth of the National Bureau of Economic Research, Vol. 24 (Princeton: Princeton Univ. Press, 1961), pp. 449–98Google Scholar.

³¹ For a criticism of the estimates given by Lebergott, as well as for those given by Gallman, Towne and Rasmussen see Fishlow, Albert, ”Trends in the American Economy in the Nineteenth Century,” Review Article, The Journal of Economic History, XXII, No. 1 (March 1962), 71–80Google Scholar.

³² Historical Statistics, Series D-37, p 72; Stanley Lebergott, “The Pattern of Employment Since 1800,” in American Economic History, pp. 281–310.

³³ So as to make the patent totals of 1879, 1884, and 1889 comparable to the pre-1874 totals, the totals for 1879 were centered on 1878 and similarly for 1884 and 1889. Thus, when, for example, patents are lagged one year, the three-year-centered total for 1844 is computed by summing the individual totals for 1841, 1842, and 1843; the centered total for 1879 is computed by summing the individual totals for 1875, 1876, 1877. Only nine observations are available when the patent series are lagged more than one year, there being no data available before 1837.

³⁴ Coefficients of determination are not corrected for degrees of freedom.