In many parts of France, dog-power was vital to the early industrial revolution. In the Ardennes, where nail-making was a major domestic industry, a passer-by who peered into one of the nail-makers’ low stone cottages would see a small dog scampering inside a wheel to keep the bellows blowing. In the Jura, villages without a water supply used wheel-spinning dogs to run machines. The usual stint was two hours, after which the dog, slightly singed by flying sparks, went to wake its replacement and could then do as it liked. The humans worked for up to fifteen hours a day and were often stunted, myopic and claw-fisted. The dogs seemed to have been better adapted to the task.