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PREFACE.

The author's principal aim in preparing this volume has been, as its title indicates, to serve that large class of young engineers who, like himself, have not liad the advantage of a technical education before going out for their livelihood.

The initial chapters are, therefore, given to a compendious exposition of those mathematical truths and methods which they must needs become familiar with from the beginning. Plane Trigonometry, Logarithms, and propositions relating to the circle, are tools of the craft in constant use; ready handling of them is an indispensable condition of excellence. Be not discouraged by obscurities and difficulties at the outset; light will gradually break on the scrutinizing eye, and a way always open to manful effort.

These chapters are followed by instructions as to the adjustment and use of instruments, and hints concerning field routine, which it is thought will be found acceptable to the inexperienced learner. The same may be said of the articles on staking out work, and those on track problems, with which the text of the book closes. They have been written with the author's own early ignorance in mind, and with a wish to set the subjects forth as plainly as possible, disembarrassed of hard words in the description, and of unpractical niceties in the operation.

The chapter on field location is believed to include all the problems likely to occur. The author, in compiling it, lias taken those only which have arisen in his own practice, and which, therefore, may arise in the practice of others. His

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use.

own practice having been unusually large and diversified, probably the examples given will prove adequate, directly or indirectly, to all contingencies.

No attempt has been made to swell the bulk of the volume with imaginary cases; the object being, not to provide barren mathematical exercises, but to teach useful knowledge.

Problems, also, affecting location in its economical aspects, -- the balancing of physical and financial conditions, equating of alternative lines, and the like, - do not come within the scope of the work, and are therefore not created.

Considerable pains have been spent on the tables. However far the young engineer may eventually outgo his teacher as regards the text of the book, these are implements of his art which never become antiquated, and can never fall into dis

Those herein contained which are original will, it is hoped, be esteemed worthy of place with their well-approved associates.

The author invites friendly criticism: he would be pleased to receive suggestions, both for the improvement of the book, and for the correction of possible errors in it, should another edition be called for.

In dismissing the work from his hands, the precarious. snatches of time occupied in its preparation, by day and by night, during the past two years, which might have been more agreeably spent in reading, talking, or musing, recur to the writer's mind; and the thought arises, To what end or from what motive do people undertake these technical labors? Why should Forney and Bourne toil to simplify steam for our apprehension; Nystrom to compile mechanical, Molesworth and Trautwine to epitomize civil engineering; Henck to prepare his elegant manual of field mathematics; Box to illustrate hydraulics; and Shreve, with lucid pei, to make clear for us the strains in truss or archi? The ordinary motives to endeavor here have no place. There is neither fame nor profit

to his book; he remains impersonal, -- known but indirectly, and but to a class. How, then, shall we account for his labors? I take it, the Father of mankind has not only made our minds to hunger for knowledge as our bodies for food, but has also imposed upon us a kindly law of communion, by virtue whereof we cannot do otherwise, without violence to generous nature, than share with our fellows whatsoever we have learned that seems new and useful. Under this law these beneficial works would appear to have had their being, and thus pure are they from the stain of selfish aggrandizement.

Though the present writer would not arrogate equal fellowship in the eminent brotherhood named, yet he may justly claim like pureness from unworthy motive, and certainly feels like comfort at heart to that which they must know, for having discharged, in what measure it has been laid upon him, the divine obligation.

WM. F. SHUNK. RAHWAY, N.J.

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