“_Among the first things a practical engineer should know, and among the last things he will, after becoming such, forget, is that in handling water within pipes he has a fluid which, while it is flexible to the greatest extent and is susceptible of the influence of power, or force, of greater or less intensity, and while it may be drawn from below and raised to the heights above, can be turned to the right or to the left at will, and while, with a seeming docility which is as flattering as it is deceptive, it bends itself to the will of the engineer, still there are some things it will not do, and which all the complicated appliances of the engineer have as yet failed to compel it to do. When inclosed within chambers and pipes, to an extent that fills them, it will not permit the introduction of an added atom without bursting its bounds. While inclosed within long lines of pipes it will not suddenly start into motion, or when in motion suddenly come to a rest, without shocks or strains more or less disastrous; and so, while it seems to be handled with the greatest ease, it is only in the manner it chooses to go, and all mechanical appliances not designed with reference to following these imperative laws are sure to meet trouble, if not disaster. In other words, when an unyielding force meets an unyielding resistance, their coming together means a shock to all about._” INTRODUCTORY CONSIDERATIONS “_Whenever a full mind meets an empty one, it is a call to teach, not to scoff._”—ANON. [Illustration: ORIFICES OF PIPES, ETC., SYMBOLICAL OF IRRIGATION.] “_He who sedulously attends, pointedly asks, calmly speaks, coolly answers and ceases when he has no more to say, is in possession of some of the best requisites of man._”—LEVATER. PREFACE. It should be a matter of thankfulness to author and reader, or rather to both instructor and student, for this is designed to be an educational work, that the Laws of Nature are unchangeable. From age to age and co-extensive with the globe the immutable principles underlying and actuating the physical states of all matter remain steadfast; gaseous bodies expand by unchanging laws which are obeyed down to the merest atom, fluids flow by law and the earth to the smallest particle remains firm, all things at all times responsive to the mandates of the Author of Creation. The silent, mighty, unanswering physical characteristics of Gravity, Cohesion, Tenacity, furnish an agreeable contrast to the din, discord and frequent argument, to the verge of hatred, that have too often accompanied the efforts of mankind to co-operate with the forces of Nature. But now, between author and reader, let it be hoped, that in the unfolding of the subject-matter of this work that kind consideration will be extended and that some of that peacefulness and trust which existed on the earth, when flints were the weapons and the gourds the only goblets, may prevail from beginning to the “finis” of the volumes.