3. The work is written in accordance with modern theories and practice; no exertion has been spared in the attempt to make it fairly represent the latest state of the science of hydraulics and its adaptation to the needs of modern mechanical advancement, i.e., in the line of practical hydraulics.
Note.—The preface is almost invariably made after the book itself is finished, for an author never knows with much exactness whither his researches will lead him. The book he begins is not always the book he finished; this is especially the case with books relating to modern sciences and industry. As an instance of this, it may be told that at the commencement of this work it was generally agreed that the easy “lift” of the centrifugal pump was some sixty or eighty feet, and not much more, but the appropriate section relating to centrifugal pumps has reached a lift of two thousand feet had been practically assured by recent discoveries. This important difference demanded a change in the writing although—as it happened—not in the printing. This, to explain why here, the author gives generous praise to others who have assisted in the long task of making these volumes.
4. It has been made by “men who know for men who care,” for the whole circle of the sciences consists of principles deduced from the discoveries of different individuals, in different ages, thrown into common stock; this is especially so of the science of hydraulics; thus it may be truthfully owned that the work contains the gathered wisdom of the ages, utilized wherever the author has found that it would increase the usefulness of the volumes.
5. It is a work of reference minutely indexed. We are warned by Prof. Karl Pearson that “education can only develope; it cannot create. If a man has not inherited ability to learn, education cannot make him learn,” but in a well indexed book, simply and plainly written, both classes referred to are equally benefited.
There came the moment, once upon a time, when the author of this book, in his eager pursuit of knowledge, asked one question too much, to which he received the “gruff” answer:
“Look ahere, I don’t propose to make a dictionary of myself.”
This was a painful retort from a man already under large obligations to the questioner, but it had its reason in being spoken. There are things in the way of a man’s own craft that he most unwillingly imparts to anyone else.
It is not thus with this work; nothing has been withheld that would make it plain and helpful to one in need of the special line of information aimed to be conveyed in its make-up.
In making acknowledgment for favors received the author first remembers Mr. Alberto H. Caffee who arranged in behalf of the L. Middleditch Press for the issue of the work. Mr. Caffee’s name appears in the dedication, with that of the brave soldier and accomplished gentleman Maj. Abram B. Garner.
The latter is one to whom “Jove has assigned a wise, extensive, all considerate mind.” The author is proud to call him friend and to acknowledge the benefit received in kindly advice relating to his productions.