John McAdam

John McAdam, the inventor of tarmac around 1816, appears as one of the new men who drove successive waves of transport innovation in industrializing England. His example gives a concrete human scale to the book’s argument that economic change depends not only on technology, but also on the institutions that shape incentives and on historical circumstances that can open or obstruct change.

Identity and Contribution

McAdam was a road innovator, identified with the invention of tarmac around 1816. The account sets road building within a sequence of English transport developments: canals first, then roads, and finally railways. These advances connected manufacturing areas and helped move both industrial goods and the materials needed to produce them.

The book stresses how little the leading road and railway innovators’ earlier lives necessarily prepared them for transport engineering. McAdam was the second son of a minor aristocrat; the text gives no further account of his training or the circumstances of his invention. His brief appearance is therefore not a detailed biography but an instance of a broader pattern: transformative work could come from people whose previous connection to the new field was limited or indirect.

Innovation and Industrial Change

The transport sequence unfolded alongside the expansion of industry. Canals began developing in England after 1770 and, by 1810, linked many of the principal manufacturing areas. They lowered the cost of moving bulky finished goods, including cotton textiles, as well as inputs such as raw cotton and coal for steam engines. Roads and railways followed as later waves of transport innovation, with McAdam associated with the road-building phase.

This account presents innovation as part of a wider process rather than as an isolated invention. New technologies helped reorganize economic activity; their development and use depended on people willing and able to work beyond the established routines of older industries. In cotton manufacturing, for example, only about one-fifth of leading industrialists had previously been involved in anything like manufacturing. The contrast between inherited experience and new fields of activity clarifies why McAdam’s place among the transport innovators matters even though the evidence does not describe the technical details of tarmac.

Institutions and Historical Divergence

The book’s larger argument is that institutions shape the incentives to invest, innovate, adopt new technologies, and participate in economic life. Political institutions determine how power is distributed and whether citizens can constrain politicians; economic institutions in turn influence who can enter markets and who benefits from economic activity. McAdam’s invention is situated within this framework, but the text does not attribute his work to any particular policy, patron, or institutional decision.

The discussion also resists treating innovation as a guaranteed route to lasting prosperity. Extractive institutions can produce some growth when political power is sufficiently centralized, but elites who benefit from the existing order may resist innovation because creative destruction unsettles established economic arrangements and political relationships. Sustained growth therefore depends on more than new inventions: it requires conditions in which change can continue rather than be suppressed.

That distinction fits the book’s account of historical divergence. Small institutional differences accumulate through institutional drift, but their consequences become especially pronounced at critical junctures, when disruption changes the balance of power. The Industrial Revolution is one such juncture: it offered the potential for rapid economic transformation, while also threatening established structures. McAdam’s tarmac invention belongs to this history of transport change, but the broader argument is about why societies respond differently to opportunities for innovation—and why those differences shape their longer-term paths.