Cyclopedia of engineering; a general reference work on steam boilers and pumps; steam, stationary, locomotive, and marine engines; steam turbines; gas and oil engines; gas-producers; compressed air; refrigeration; elevators; heating and ventilation; management of dynamo-electric machinery; power station; etc. Editor-in-chief: Louis Derr, assisted by consulting engineers, technical experts, and designers of the highest professional standing; illustrated with over two thousand engravings. Volume: v.7 (1919)