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TABLE OF CONTENTS.

CHAPTER I. GENERAL OUTLINE OF THE SYSTEM OF CARRYING ON A TRIGONOMETRICAL SURVEY

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CHAPTER II.

MEASUREMENT OF A BASE LINE.

Description of the different Methods that have been adopted to ensure its correct Measurement.—Combined Iron and Brass Rods used on the Ordnance Survey.-Visual Contact with reading Microscopes.-Reduction of a Base measured on any elevated Plain to its Value at the Level of the Sea.-Prolonging and verifying a Measured Base by Triangulation.

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CHAPTER III.

TRIANGULATION. Choice of Stations.—Method of rendering distant Stations visible-by Reflection of the Sun's Rays-Argand Burners-Drummond's Light.Method of increasing the Length of the Sides of the first Triangles directly from the Measured Base.—Secondary Triangles.-Assumed Base.—Instruments used for observing Angles on the Continent and in England.-Reduction to the Horizon.-Spherical Excess.-Reduction to the Centre.Adjustments of a Theodolite.—Method of discovering lost Stations.Laying down a Triangulation upon Paper.—Position of Trigonometrical Stations also ascertained by astronomical Observation

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CHAPTER IV.

INTERIOR FILLING-IN OF A SURVEY, EITHER ENTIRELY OR

PARTIALLY, BY MEASUREMENT. Method of Filling-in the Detail entirely by Measurement, as practised on the Ordnance Survey.—Levelling Marks and Forms of Field-Books, &c.— Measurement of Roads by the Chain and Theodolite.-Computing the Contents of Enclosures directly from the Field-Book.--Filling-in the Interior, partly by Sketching.-Road Surveying.–Variation of the Compass.—Sketching between Trigonometrical Points and Measured Lines.Practical Methods of avoiding Obstacles and determining inaccessible Heights and Distances in the Field.-Station Pointer.-Surveys for Railways

30 CHAPTER V.

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COLONIAL SURVEYING.

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Difference between the Objects in view in the Survey of a Cultivated

and that of a new Unsettled Country. First Operations.—Preliminary Ex-

ploration.— Objects to be principally considered.—Sites of Townships.-

Main Lines of Communication.—Guides for marking on the Ground the

Divisions of Properties.—Size of these Divisions.—Precautions to be ob-

served to secure to the Public Rights of Road, &c.—Necessity for Extensive

Surveys on the First Settlement of a New Colony.—Deviations from Gene-

ral Rules in laying out Sections.-Frontages on, and Access to Rivers and

Main Roads.—Sectional Roads.—Monopoly of Water to be guarded against.

-Sections laid out in Broken Irregular Ground.—Statistical and other In-

formation to be fully afforded to Settlers.--Marking Boundaries of Sec-

tions and Roads._Reservation of Rights of Road.-Natural Features of

Ground.—Geological and Mineralogical Specimens, and Meteorological

Register, &c.—Usual Method of marking Regular Figures upon the Ground.

-Necessity for a Triangulation to conduct these Operations with any degree

of accuracy when upon an extended Scale.—Advantage of Carrying it on

rather in advance of the Sectional Surveys.-Other Uses of the Triangula-

tion.-District Surveyors.-Surveying by Contract.-Rate of Progress and

Cost per Acre of the Sectional Survey and Marking out Roads.-Cost of

the Triangulation.—Method of Survey pursued in the Canterbury Settle-

ment, New Zealand.—Temporary Division of Land for pastoral Purposes.

-Territorial Division of Counties, Hundreds, &c.—Remarks on Exploring

Expeditions.—Method of Proceeding - Objects in View, and collateral In-

formation to be obtained

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IV.-TO FIND THE LOCAL TIME.

which the Time at some fixed Meridian is known.

2. By Signals.

3. By the Transmission of Chronometers between Stations.

4. By the Eclipses of Jupiter's Satellites, and the Eclipses of the Sun and

Moon.

5. By Lunar Observations.

6. By the Method of Moon-culminating Stars.

7. By Occultations of fixed Stars by the Moon

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VI.-TO FIND THE DIRECTION OF A MERIDIAN LINE, AND THE VARIATION

OF THE COMPASS.

1. By the Azimuth of any Celestial Object.

2. By the Amplitude of the Sun at his rising or setting.

3. By equal Altitudes ard Azimuths.

4. By a Transit Instrument when properly adjusted in the Plane of the

Meridian

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