In this paper, we argue that together with individual inventors and firms, what Robert C. Allen (1983) has termed as collective invention settings (that is settings in which rival firms freely release each other pertinent technical information), were also a crucial source of innovation in the industrial revolution period. Until now, this has been very little considered in the literature. This paper focuses on one of these cases: the Cornish mining district. In Cornwall, during the early nineteenth century, a notable collective invention setting, gradually emerged. This case is particularly remarkable because it was capable of generating a continuous and sustained flow of improvements in steam pumping technology which in the end greatly cont...