This is a reprint of the first edition (1919) of a handbook that engineers of all types have found it useful. Originally published by Compressed Air Magazine, it collects under one cover formulae and data on compressed air engineering essential to an understanding of its theory and practical application. It is unlike any other book on the subject, in that it involves no discussion of the details of design and construction of pneumatic machinery of the several manufacturers, but confines itself strictly to those things which every user of such equipment should know, to enable him to derive the greatest benefit from his investment. The volume avoids, generally, the formality associated with a strictly technical work and favors the attention of the busy executive, while at the same time proving a valuable aid to the engineer and student.