economics and engineering. Engineering and economics are inseparable. Indeed, they are linked in one of the most quoted and paraphrased definitions of engineering, which comes from the self-made engineer Arthur Mellen Wellington (1847–1895). In 1876 he published a series of articles on railroad layout in the Railroad Gazette, which the next year were published as a book. A decade later, a greatly expanded and revised edition was published as The Economic Theory of the Location of Railways: An Analysis of the Conditions Controlling the Laying Out of Railways to Effect the Most Judicious Expenditure of Capital (New York: Wiley, Engineering News, 1887). The now-classic definition reads:

This is often found paraphrased in a shorter version to serve as a definition of an engineer: “An engineer is someone who can do for one dollar what anyone can do for two.” The definition has become so familiar that it is frequently cited, in various modified forms, without association with Wellington. Thus, Nevil Shute used it as an epigraph for his posthumously published novel, Trustee from the Toolroom (New York: Morrow, 1960): “An engineer is a man who can do for five bob what any bloody fool can do for a quid.