This dissertation is about energy; specifically how prime movers changed at the beginning of the Industrial Revolution. These power needs are explored via the history of the Newcomen atmospheric engine, as it was used in the 18^th century to drive pumps in flooded mines. This approach examines society as an energy-converting phenomenon, and uses the concept of an energy rent.

The dissertation seeks to reach past the 19^th century's "high-pressure historiography" of the first engines powered by fire; instead, it traces the actual low-pressure atmospheric technology of the first commercially successful engines, and the surprising, rather than inevitable, transformation they engendered. The costs of fuel are shown to be an essential factor in the success or failure of the first Newcomen engines. Thomas Newcomen's failed first attempts in Cornwall (1710) are contrasted with success in collieries, located in the relatively distant region of the Midlands, only two years later.

To test the suggestion that coal is needed for a Newcomen engine to be profitable, two detailed case histories compare 18^th century engines, both fired using wood fuel, at iron ore mines. The first was a failed engine at Dannemora, Sweden (1728); the second a successful machine built by the Brown brothers at Cranston, Rhode Island (1783). The Brown engine's case history was based on extensive original archive research, and also provides a detailed history of the Hope Furnace, which used the ore from Cranston. Success for the Browns in Rhode Island is found to have been rooted in their careful planning for fuel needs. The two mines were also found to have significantly different construction of gender roles, suggesting the Rhode Island context had established more thoroughly capitalist relations.

The work shows that the demand for more extensive power, which led to these engines, was propelled by the ability of the evolving commercial market place to convert energy profitably (16^th and 17^th centuries in Europe). The resulting pressure to expand society's energy envelope created this "need" for primary power, which was particularly acute at mining enterprises. A vocabulary for cross-comparing primary movers is developed. The Newcomen engine is found to have teetered on the border between negative and positive energy rents. The dissertation concludes that it tipped positive, when applied in an energy intensive environment, thus contributed to a divergence from the equilibrium of an advanced agricultural society.