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Geometrical demonstrations are avoided, except in a few cases, the design of the writer being to furnish a short treatise, to direct at once to what is required.

The work will be comprised in four divisons: 1st. The arithmetical calculation of plane figures.

2nd. The calculation of surveys taken with the compass and chain by latitude and departure, with various methods of proof.

3d. The method of plotting, enlarging and diminishing maps, with remarks on copying and embellishing

4th. Levelling, profiling and calculating cuttings and embankments, the use and application of the tables, together with many other useful things applicable in practice.

PREFACE.

The following compilation is made in consequence of the undersigned not having met with any work on Surveying sufficiently concise, and instructive in the several details, necessary to qualify properly the practical surveyor. Many of the works already published contain subjects not necessary in such treatises; such as Geometry, Plane Trigonometry, &c., which subjects, it is taken for granted, all who intend to become proficients have studied prior to reading Surveying. They are also found not to contain instruction that in recent improvements the surveyor requires to know. Many of these things the compiler of this short treatise, will endeavour to supply; also, many other necessary things, which, in his long experience, he has found indispensable to the correct practitioner. He has collected the most necessary instruction in leveling and profiling, with a new and speedy plan of setting grades on rail and plank roads. The method of inflecting curves, not hitherto sufficiently explained. The description and design of a new instrument whereby distances are found at once without any calculation. A new method of surveying any tract of land by measuring one line through it, with a geometrical demonstration of the same. metrical method of correcting surveys taken with the Com1 *

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pass, to fit them for calculation, with a table of corrections for certain distances, but applicable to all. A short method of finding the angles from the courses, and vice versa. The method of surveying with the Compass through any mine or iron works, and to correct the deflections of the needle by attraction. Description of an instrument by the help of which any gentleman may measure a map by inspection, without calculation. A new and short method of calculation, wherein fewer figures are used than in the common method; also, the Pennsylvania method. Tables of difference of Latitude and Departure, made expressly for two pole chains, but which can also be used with four poles. The method of correcting the diurnal variation of the needle, most useful in tracing the boundaries of surveys, a complete description of which is given with the reason for using 57-3° and how it is found. Various methods of plotting and embellishing maps. The most correct method of laying off lots with a pole, plummets, &c. Description of a new Compass which the compiler has contrived for that purpose, and which is made by Reid & Sons, Smithfield street, Pittsburgh.

The compiler does not deny that he has borrowed from many authors those things he has found best adapted to the completion of a work adequate to make a finished American Surveyor, of which an unprejudiced and enlightened public are the best judges. •

ANDREW DUNCAN,
Land Surveyor and Civil Engineer,

Office, Odeon Building, Fourth St., Pittsburgh.

PRACTICAL SURVEYOR'S GUIDE.

PROBLEM FIRST. To reduce two pole chains and links to four pole

ones.

If the number of chains be even, the half of them will be four pole ones, to which annex the given links. Thus:

1. In 16 chains, 37 links of two pole chains how many four pole ones :

2)16. 37

Ans.

8.37 But if the number of chains be odd, take half of them and add 50 to the links. Thus:

2)131.40

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PROBLEM SECOND. To reduce four pole chains and links to two pole ones. Double the chains and annex the links if

they be less than 50, but if they exceed 50, add one to double the chains and take 50 from the links. Thus: 16.25 of four poles, how many two pole chains.

16.25
2

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22. In 19.87 four pole chains how many two pole ones.

19.87

2,50

Ans. 39.37

To reduce two pole chains and links to perches and decimal of a perch, multiply the chains by two and the links by four, thus: In 16.37 how many perches.

16.37
2. 4

Ans. 33.48

ARTICLE FIRST-OF AREAS. A square is a plane figure having four equal sides and four right angles. To find the content,

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