This talk examines how American foreign relations and national security between 1840 and 1920 were shaped by developments in geology, steam engineering, and the science of logistics. At the same time, technical experts trained their research on the combustion and distribution of coal, the design of steam engines, and the rational management of resources to address new challenges faced by the United States’ growing power in world affairs. This history examines how a new energy technology answered old problems while creating new ones.