New evidence demonstrates a link between labor scarcity and the adoption of labor-saving technology in industrializing England. During the Napoleonic Wars, more than 10% of the male population served in the armed forces. Where recruitment was heavy, more machines economizing on labor were adopted. Naval recruitment, instrumented by warships’ coastal access, provides exogenous variation in labor scarcity and suggests that the link between labor shortages and adoption is causal. Where mechanical skills were abundant, the impact of labor scarcity on adoption appears to be larger.