TECHNOLOGY AND CULTURE Book Reviews 851 screw companies. Before the 1920s automatic lathes were limited almost exclusively to the production ofscrews or other products that could be machined from wire or metal rods. In the sewing machine industry, where automated, multifunction turret lathes received their widest use, they accounted for only one-sixth of all machines. This hardly amounts to automated “mass production,” as distin guished by David Hounshell from the American system. Ruby does not discuss such distinctions, however. Instead he dedicates an entire chapter to the definition of what we mean when we say “machine tool” as opposed to “automatic machine tool.” Here his conclusions seem soft. Unlike Hounshell, who pointed to international debates about the “American system” in the 19th century and about “mass production” in the 20th, Ruby’s definitions seem useful only as de scriptive terms of historiographical debates: “In the 1880s,” Ruby tells us, “the theme of automation was not yet discussed” (p. 135). Thus even if various industries were finding a few specialized pur poses for automation, engineers and workers did not yet conceive their daily work in the terms Ruby puts forth. The book is no less valuable, however, for Ruby is honest about making his distinctions: this is not “Whig” history. And he is right to uncover neglected precedents in mass production. His lathes are older than and at least as important as, say, the Chicago pork pro cessing plants—whose technology was quite a bit farther removed from assembly line tools than the machines that Ruby richly de scribes. Michael Allen Dr. Allen teaches in the School ofHistory, Technology, and Society at the Georgia Institute of Technology. Regulation and the Revolution in United States Farm Productivity. By Sally H. Clarke. New York: Cambridge University Press, 1994. Pp. xiv+310; illustrations, maps, figures, tables, appendices, notes, index. $59.95 (hardcover). The question ofwhy people adopt technological innovations, and why they do not, has had a sturdy but unresolved life among histori ans of technology. It has never been easy to explain the ultimate success or failure of technologies without sounding either Whiggish or overly deterministic. For many economists, the acceptance or re jection of technology can be accounted for by invoking the behavior ofrational actors and market forces. This sort ofexplanation, unfor tunately, often sounds flat and unpersuasive to historians: surely the explanation is more complex, more ambiguous, than mere bottom lines would suggest. In the field of agricultural history, however, eco nomic explanations are abundant and in fact dominate the entire 852 Book Reviews TECHNOLOGY AND CULTURE discourse of adoption. Somehow, scholars in agricultural history are themselves satisfied with such accounts. Sally Clarke is an economic historian who chafes at the economic reductionism so often encountered in histories of technology and agriculture, and in this book she tries to provoke some new ways of looking at innovation. Her questions are these: why did midwestern farmers adopt technologies in the 1930s but not in the 1920s, despite evidence that adoption in the 1920s would have made economic sense? And what role did New Deal regulation play in their calculus? Clarke looks closely at three new technologies: the tractor, the me chanical corn picker, and hybrid corn. The tractor, she argues, was the most important technology avail able to farmers in the 1920s and promised a good return on invest ment. Most economists would argue that a farmer would certainly have purchased a new tractor because it would have increased pro duction and thus the farmer’s profit. Yet very few midwestern farm ers bought a tractor before the mid-1930s. Why? Clarke suggests sev eral reasons, all having to do with a poor “investment climate,” which is an amalgam of rational and irrational factors that shaped farmers’ reasoning. First, tractors required a big cash outlay, which, while not important to economists studying aggregates, was very im portant to individual farmers struggling with the post-World War I market downturn. Second, farmers were worried about market prices for their commodities over the short term. And third, the lending policies of banks during this period were neither generous nor flexible. Thus, farmers came up with a production strategy that made sense overall, even...