摘要
Diagrams are ubiquitous in economics and are uncontestably among the most used, if not the most important workhorses of economists, though they come in many forms. This essay examines the different uses ofgraphs and diagrams in the pionering work of two Victorian economists, Stanley Jevons and Alfred Marshall. We stress the difference betwen their use as representations and as visual reasoning tools, a difference that became obscured in the twentieth century with the rise ofeconometrics.