This is an incomplete set of three books of the Audels Engineers and Mechanics Guide. It includes books 3, 4, and 8.
Book three is about locomotive marine turbine engines and indicators.
Book four is about gasoline oil engines, producers, and aviation.
Book eight is about writing and electrical references illustrated.
These books are one of the best physics informative books with the highly detailed descriptions and drawings of all of the components ranging from a vast variety of steam engines, gasoline oil engines, wiring and electrical information.