Changing the Perception of Time : Railroads, Access to Knowledge and Innovation in Nineteenth Century France

This paper exploits an episode of French history to study the relationship between the roll-out of railroads and the rise of the innovation activity. I take advantage of the exogenous variation in railway access arising from a straight-line time variant instrument to document that access to rail network increases the regional innovation activity, as it is proxied by the number of patents in the historical database of the National Institute of Industrial Property of France. I employ an access to knowledge index as an underlying mechanism behind the main results to show that, by reducing least-cost distances between cantons, railways intensified the influence exerted by neighboring concentrations of inventors, thereby triggering the spread of patenting. Next, I study the role of a global city, such as Paris, on the diffusion of new technologies. To do that, I have first to use a machine learning algorithm for text analysis and to assign a technology to the patent applications without a technological class. Finally, I introduce a back of the envelope exercise based on canals and roads to show that in the absence of railroads the invention rate of the French cantons would have been, on average, 24.14% lower