In the second edition I have endeavored to utilize such constructive criticisms of the first edition as came to my attention. Five plates are used to illustrate engine details and each part is named on the plate itself. The first chapter now includes a number of calculations of a general character which were introduced to give the student a better view of the entire subject. The boiler, the engine, and the condenser are brought together so that the functions of each form parts of one picture in the student's mind. The inertia of the indicator piston and two of the difficult cases in the Zeuner valve diagram construction are discussed. The addition of tables and diagrams facilitates finding loss of head in steam or air pipes. The discussion on Hirn's analysis is now followed by very complete tables giving the mean effective pressure and the steam per horsepower-hour for condensing and for non-condensing engines of the four-valve type. Tables of corrections for initial condensation under various pressures are also given. A comparison of the ideal and practical consumption of steam under a variety of circumstances may thus be made quite easily.
The engineer has to deal with the transfer of heat through metal surfaces. Prof. Perry's theory of heat transfer and formulas for finding the mean temperature of the heating and cooling fluids, as well as for finding the rate of heat transfer per square foot per minute per degree difference in temperature, as given by Hausbrand, have been added. A much more complete discussion of the design of feed-water heaters and air-pumps both wet and dry for surface, jet or barometric condensers is presented.