First published in 1936, as the second edition of a 1920 original, this book was written to provide engineers with a working knowledge of elementary thermodynamics. The principles of the subject are first introduced in a non-mathematical form and applied to practical problems. Once the principles have been established on this basis they are discussed in mathematical terms. The text was written by the renowned Scottish engineer and physicist James Alfred Ewing (1885–1935) and the revised second edition was published posthumously with his amendments. This book will be of value to anyone with an interest in thermodynamics, engineering and the history of science.