PREFACE.

THIS book has been prepared expressly for the use of the upper forms in schools and colleges. The school works, hitherto in use, have been scarcely so much works on surveying, as compendiums of mensuration, heights and distances subjects, which may be fully understood, without the student being in the smallest degree enlightened as to the best methods of practical surveying adopted in the present day. And whatever small portion of their contents may have been devoted to Land Surveying (properly so called), they are faint and imperfect sketches of bad systems long since exploded; going, it is true, upon the old and favourite plan of accumulation, or of working from part to whole-that of "adding field to field and acre to acre," but producing a distorted representation of the positions of each, and a very incorrect sum total of the whole. This system has been found to be so very defective, and the opposite one,

of working from whole to part, has so entirely superseded it, that whatever little a lad may have learned of Surveying at school by the old method, has to be unlearned again, before he can clearly imbibe the new.

In introducing this new system in the present work, which is respectfully but confidently submitted to the notice of the public, the Author has therefore endeavoured, and he hopes successfully, to present it in a form, suited from its simplicity to the understanding of the young, and explained and illustrated with such diagrams and practical field notes (arranged in the way adopted by surveyors in the field) as cannot fail to impress the principles indelibly on their minds.

The subjects treated of here will be found to go beyond what are generally introduced in school books; but in treating briefly upon many subjects, and explaining the first principles of each method of Surveying, whether by the CHAIN, THEODOLITE, or CIRCUMFERENTOR, or lastly that of LEVELLING, the Author has considered, that in going fully and minutely into their first principles, he has better consulted the interest of the student, than in taking up any one subject, and dwelling upon it to the exclusion of the rest, more amply than the young mind can at an early age properly comprehend.

The work is divided, like the Author's larger work, into

four heads: the Chain, Theodolite, and Circumferentor Surveying; and Levelling, treated simply but fully, so that the student can, if deemed necessary, at once proceed to the study of the larger work, which treats upon the several subjects more practically and scientifically.*

The examples attached to each Rule are such, that the pupil, who carefully studies them, cannot help becoming master of the subject-he will certainly have nothing to unlearn, should he afterwards follow it professionally.

It seems almost unnecessary to offer any apology for writing a work of this kind in the present day, when the necessity of keeping pace with the times, and of making the education of the young more practical and scientific than has hitherto been the custom, is taken into consideration. The field application of the principles of surveying must inevitably tend, by the use of the various instruments alone, to give a tone to the mind, and encourage a fondness for science, at the same time that it presents to the understanding the usually dry subject of the mathematics in a much more familiar and interesting form than could be done without it.

Nothing is more pleasing to youth, than learning acquired by the use of the eyes. A problem explained and carried

* Castle's "Engineering Field Notes." Simpkin and Co.

out before them, will be impressed on the mind much more clearly and permanently than one that is merely addressed to their understanding.

The Author can now speak from experience. He has proved from the number of copies sold of the work that the opinion which he expressed in a former Edition was perfectly correct, viz., that at one time or other in places of education this subject would become a favorite one.