Drawing on nineteenth-century German and English economic historians, Franklin Mendels formalized a theory of "protoindustrialization" around economic growth as it occurred in eighteenth-century England and France. 1 Economic activity concentrated in growing cities at regional, subnational levels as supplies of labor migrated toward both work and markets; manufacturing and agriculture shared a single unskilled labor force that was the primary engine of growth; the major markets for both agricultural produce and industrial goods were international; technological innovations affected both agriculture and manufacturing. During early protoindustrial growth, Mendels theorized, rapid rates of innovation and change would have little macroeconomic effect beyond a local "spurt" of rapid growth as increasing incomes based on a brief competitive advantage brought population increases that broke the historic balance between labor supply and subsistence wages. After a lag of one-two generations, however, this imbalance would become the labor surplus to drive sustained growth in the Industrial Revolution. Thus the result of Mendels' theory was the need for continuing rapid technological innovation and economic change to sustain a permanent imbalance between labor supply and wages. Self-sustaining growth was only possible after a long period of permanent economic instability and social turmoil.
Mendels did not theorize at the microeconomic level explored by Maxine Berg, and thus missed the powerful effects of these changes on
productivity and output in individual industries, establishing above all a trend of improvement in each sector. But the experience in the eighteenth century was of a secret but gathering force. And the change it made to the economy as a whole, though delayed, was ultimately marked and abrupt. The technological spurt and organizational changes of the eighteenth century did not make their mark on the wider economy until the decades of the 1820s to the 1840s. 2