Surveying and Levelling Instruments, Theoretically and Practically Described. For construction, qualities, selection, preservation, adjustments, and uses; with other apparatus and appliances used by civil engineers and surveyors in the field.

THE TELESCOPE AS A PART OF A SURVEYING INSTRUMENT:--General Description--Qualities--Optical Principles--Refraction of Glass--Limit of Refraction--Reflection--Prisms--Lenses, Con...

THE MAGNETIC COMPASS AS A PART OF A SURVEYING INSTRUMENT OR SEPARATELY:--Broad and Edge-bar Needles--Manufacture of the Needle--Magnetisation--Suspension--Dip and Adjustment--Li...

LEVELS:--Methods of Ascertaining--Level Tubes--Manufacture-- Curvature--Sensitiveness--Testing--Reading--Circular Levels-- Surveyors' Levels--Y-Levels--Parallel Plates--Adjustme...

MINING SURVEY INSTRUMENTS:--Circumferentors--Plain Miner's Dial-- Sights--Tripod Stand--Adjustments--Henderson's Dial--Lean's Dial--Adjustments--Hedley's Dials--Additional Teles...

INSTRUMENTS TO MEASURE SUBTENSE OR TANGENTIAL ANGLES TO ASCERTAIN DISTANCES:--Historical Notes of the Method--Principles Involved-- Stadia Measurements, Direct and by the Ordina...

GRAPHIC SURVEYING INSTRUMENTS AND APPLIANCES CONNECTED THEREWITH:--Plane Tables--Alidades--Telescopic Arrangements-- Subtense Measurements--Various Devices for Holding the Paper...

INSTRUMENTS FOR MEASURING LAND AND CIVIL WORKS DIRECTLY:--Chains-- Various Tellers--Standard Chains--Arrows--Drop Arrows--Vice for Adjusting Chain--Caink's Rule for Inclines--St...

MISCELLANEOUS SURVEYORS' AND ENGINEERS' INSTRUMENTS, APPLIANCES, AND ACCESSORIES:--Cross Staff--Mechanics' Levels--Boning Rods-- Footner's Railway Gauge--Girth Strap for Timber...

1.--=Historical Sketch.=--Although the aim of this work is to show the state of the art it is intended to represent at the present period, a large amount of literature, ancient...

THE TELESCOPE AS A PART OF A SURVEYING INSTRUMENT--GENERAL DESCRIPTION--QUALITIES--OPTICAL PRINCIPLES--REFRACTION OF GLASS--LIMIT OF REFRACTION--REFLECTION--PRISMS--LENSES, CONV...

THE MAGNETIC COMPASS AS A PART OF A SURVEYING INSTRUMENT OR SEPARATELY--BROAD AND EDGE-BAR NEEDLES--MANUFACTURE OF THE NEEDLE--MAGNETISATION--SUSPENSION--DIP AND ADJUSTMENT-- LI...

148.--=The Prismatic Compass=, shown Fig. 35, was invented by Charles August Schmalcalder in 1812. It is the most convenient portable instrument for reading magnetic bearings. A...

LEVELS--METHODS OF ASCERTAINING--LEVEL TUBES--MANUFACTURE--CURVATURE-- SENSITIVENESS-TESTING--READING--CIRCULAR LEVELS--SURVEYORS' LEVELS-- Y-LEVEL--PARALLEL PLATES--ADJUSTMENTS...

258.--=Levelling Staves.=--Since great improvements have been made in the telescopes used as part of all modern surveyors' levels, particularly by increasing their light-receivi...

304.--=Division of the Circle.=--_Sexagesimal Division._--All true surveying instruments depend, as their special function, upon taking the direction, or angular position, of su...

364.--=The Theodolite= is the most perfect instrument for measuring both horizontal and vertical angles by the aid of a telescope and graduated circles. For the purpose of surve...

416.--The description given in the last chapter of a 6-inch transit theodolite gives all particulars of the original Old English form, which in a general way comprises the const...

424.--_The Mechanical Tribrach Stage._--This important addition to the theodolite above described permits exact adjustment over a station. The upper plate of the tribrach with t...

437.--The plain theodolite is of nearly its original form as invented by Sisson. It still retains a limited popularity, which is principally due to its portability, being of les...

474.--Large theodolites employed upon geodetic surveys. Where the complete survey of a country has to be made, a system of large triangles is formed over the country from conven...

MINING SURVEY INSTRUMENTS--CIRCUMFERENTORS--PLAIN MINER'S DIAL--SIGHTS--TRIPOD STAND--ADJUSTMENTS--HENDERSON'S DIAL--LEAN'S DIAL--ADJUSTMENTS--HEDLEY'S DIAL--ADDITIONAL TELESCOP...

INSTRUMENTS TO MEASURE SUBTENSE OR TANGENTIAL ANGLES TO ASCERTAIN DISTANCES--HISTORICAL NOTES OF THE METHOD--PRINCIPLES INVOLVED-- STADIUM MEASUREMENT, DIRECT AND BY THE ORDINAR...

Certain instruments are constructed specially with the object of taking inclines, where this is the predominant work to be performed with them. They form an important branch of...

615.--=The Octant or Quadrant= measures angles within 90° by an arc of 45°. This instrument is generally termed an _octant_ on the Continent from the space of the divisions; a q...

697.--=Plane Tables.=--These instruments have been used for filling in the greater number of topographical surveys in all countries. They possess the merit that any intelligent,...

INSTRUMENTS FOR MEASURING LAND AND CIVIL WORKS DIRECTLY--CHAINS--VARIOUS TELLERS--STANDARD CHAINS--ARROWS--DROP ARROW--VICE FOR ADJUSTING CHAIN--CAINK'S RULE FOR INCLINES--STEEL...

779.--=Stations of Observation= vary materially according to the extent of the survey and its purpose. For geodetic works stations are raised at great expense, often in masonry...

808.--_Historical Note._--The observation that the atmosphere decreases in density with increase of height is due to Alhazen the Saracen, about a.d. 1000. By this he explains th...

MISCELLANEOUS SURVEYORS' AND ENGINEERS' INSTRUMENTS, APPLIANCES, AND ACCESSORIES--CROSS STAFF--MECHANICS' LEVELS AND CLINOMETERS-- BONING RODS--FOOTNER'S RAILWAY GAUGE--GIRTH ST...