6004149 General view of a section of the hardening shop showing part of the battery of large gas-fired oven furnaces for carburising and reheating operations (b/w photo) by English Photographer, (20th century); Private Collection; (add.info.: General view of a section of the hardening shop showing part of the battery of large gas-fired oven furnaces for carburising and reheating operations. Illustration for Engineering Workshop Practice by Arthur W Judge (new and revised edn, Caxton, c 1936).); by Look and Learn; English, out of copyright.