In Presenting this volume to the public the author completes a set of books devoted exclusively to plumbing which covers the calling from practice to contracting. The several books included in the set are: "Principles and Practice of Plumbing," "Wrought Pipe Drainage Systems," "Sewage Purification and Disposal," Plumbing Plans and Specifications," "Plumbing Estimates and Contracts" and "History of Sanitation.

These books are not disjointed fragments turned out from time to time, without reference to one another, but all are parts of one comprehensive whole, the result of a systematic division of subjects planned before any of the books were written. The object was to present to one volume the principles that underlie the practice of plumbing, and how those principles are applied to practice. In another, a thorough explanation of the wrought pipe systems of drainage together with an exhaustive description of how to handle and manipulate iron, brass and nickel-plated pipe. A third volume was to explain the art of preparing plumbing plans and writing specifications, and a fourth the principles of estimating, contracting and conducting a business.

Closely related to plumbing is Sewage Disposal and General Sanitation, so a fifth volume was devoted to the Purification of Sewage, then, that the plumber might have a proper and profound respect for his calling, a history of sanitation was written to show the antiquity of the craft, its struggles, its failures and its triumphs.

These books, the author believes cover very fully the various subjects, and contain such technical data as has long been needed by those interested in Plumbing and Sanitation.

J. J. COSGROVE

Philadelphia, Pa., June 15, 1910.