Knife grinders in Thiers, France circa 1902.

These knife grinders had the nickname of ventres jaunes or ‘yellow stomachs’ referring to the yellow dust released by the grinding wheels.

By laying face down, these yellow stomachs would save their backs from being hunched over all day.

Workers were encourage to bring their dogs to not only keep them company but to act as heaters to keep them warm by having the dogs lie on their legs!