In The Empire of Chance, historians of science Gigerenzer et al. argue that statistical thinking has been “second to no other area of scientific endeavor” in its influence on “modern life and thought” (Gigerenzer et al. 1989, xiv-xv). This article describes how quantitative descriptions of risk associated with industrialization and technological change became part of the mentality of ordinary Americans. It explains why Americans began counting accidents, tells what kinds of accidents they counted and how they counted them, and shows how statistical representations of risk were used to justify prescriptions for public policy and individual behavior. On this frontier of the empire of chance, safety experts and self-styled “practical statisticians” were the principal colonizers. Distant from the centers of academic statistical science, they compromised rigorous scientific standards of methodology and accurate prediction in order to make convincing arguments outside their circles of expertise. To convey their point of view to audiences who were not literate in the field of statistics, they created a public language that conveyed statistical ideas through metaphors, graphic representations, and other rhetorical devices. They also engaged non-experts in collecting and analyzing data and, by the 1920s, even used quantitative self-measurement as a device to convince members of the public to alter their own risk-taking behaviors.