This book, Thermal Engineering, is an outgrowth of a textbook by

the same authors, Elementary Heat Power, the first edition of which was

published in 1946.

In recent years the objectives of engineering education have under-

gone critical evaluation as a result of which curricula and course content

have been revised to place increased emphasis on the engineering sci-

ences and to de-emphasize instruction in the art of engineering. We

believe that this change in emphasis has been correct but feel that in

some instances it has been carried too far. It has been stated frequently

that the distinguishing characteristic of the cngineer is ability to design.

It is doubtful that an engineering student can study intelligently the

principles involved in the design of mechanical engineering systems and

components if such common items of equipment as heat exchangers,

prime movers, pumps, and compressors are looked upon as mysterious

black boxes or as circles or rectangles in a flow diagram. We believe

that the student must acquire an understanding of the maj or principles

of construction, operation, and performance of some of the types of

common mechanical equipment and that, from the standpoint of moti-

vation and conservation of time, such knowledge should be acquired

as early as possible in his scholastic program.