Audels Engineers and Mechanics Guide 7 is part of Frank D. Graham’s eight-volume reference series covering modern engineering practice. First published in 1921, the series was created as a practical course of study for engineers, mechanics, electricians, students, and industrial workers.

Volume 7 focuses on pipe fitting, heating, refrigeration, and elevators. Using detailed illustrations, calculations, and question-and-answer lessons, it explains how these important mechanical systems were designed, installed, operated, and maintained.

The volume includes information about piping arrangements, valves, fittings, heating equipment, refrigeration machinery, and elevator mechanisms. The technical illustration opposite the title page shows the piping and equipment associated with a steam-powered heating system.

Books such as this provided working mechanics with portable access to technical knowledge before modern digital manuals and online training. This volume is preserved as part of the museum’s complete eight-volume Audels collection.