Abstract

Usher occupied the chair of European economic history at Harvard University from 1936 to 1949 and was surely the most productive and original scholar to occupy this post. For economists of later decades, his most significant book was A History of Mechanical Inventions (1st edn, 1929; 2nd edn, 1954). In it he identified invention as a four-stage process in which the individual inventor, being seized of a problem in the presence of the intellectual and physical elements for a solution, achieves the primary insight (called by Usher the ‘saltatory act’ and by his students the ‘ah-ha!’ or ‘Eureka’ moment) and completes the invention through a stage of ‘critical revision’. Usher’s work here became noticed by economists when it was taken up by J.A. Schumpeter to form the historical basis of his descriptive and theoretical work on Business Cycles (1939) and also through its relation to the Kondratieff ‘long waves’ based on the clustering of a few major inventions at discrete points in and around the 19th century (1770–80, 1840–60, 1890–1910). At a time when economists treated technological change as an element as exogenous to economics as physical geography, Usher alone thought it worth examining as a complex socio-economic ‘thread’ in history. In this he was the forerunner of such modern students as Schmookler, Mansfield, Ruttan, Nelson and Rosenberg, though his book largely emphasized the technical (supply side) aspects of the process.