## A TREATISE ON THE PRINCIPLES AND PRACTICE OF LEVELLING |

### From inside the book

Results 1-5 of 27

Page 12

...

...

**gives**the correc corresponding to distances expressed in miles , and second for distances in chains . Table of the Difference of the Apparent and True Lev Distances in Miles . Distance in Miles . CORRECTION . Curvature . Curvature and ... Page 16

...

...

**give**some particulars in this place , and annex a description of the cause of , and a remedy for , the parallax between the wires of a levelling telescope , and the levelling staves , which is the cause of much annoyance to observers ... Page 28

FREDERICK W. SIMMS. ing a milled head attached to the telescope , which

FREDERICK W. SIMMS. ing a milled head attached to the telescope , which

**gives**motion to the slide by rack work ; this will carry both the wires and the focus of the already adjusted eye- piece to coinc de with the focus of the object ... Page 31

...

...

**give**the difference of level between the extreme points ; thus : Back sights . ft . dec . Fore sights . ft . dec . A and C ......... . 10.46 11.20 C ( C E .... 11.33 8.00 E CC G .... 7.42 7.91 Sums .. . 29.21 27.11 27.11 Difference of ... Page 33

...

...

**give**their differences of level ; the points thus selected are generally what are called bench marks , and are nothing more than marks or notches cut upon gateposts , stumps of trees , mile or boundary stones , or any similarly ...### Other editions - View all

### Common terms and phrases

50 base adjustment approximate point b₁ b₂ back sight back staff bench mark calculations centre line centre stake chain clinometer Cloth computed half width construction correct cross wires curvature curve cuttings and embankments datum line depth of cutting determined diagram difference of level direction distance Dover Castle Dumpy Level earth edition engraving equal example field-book Folkstone Foot of bank Fore Sight forward reading forward station give gradient ground Gunter's chain horizontal line hypothenuse Hypsometry Illustrated inches inclined plane instrument J. P. WHITNEY length line A B lines of railway mean height measured Merrimack River method middle area mile object glass observer obtain outer rail parallax perpendicular placed plates point a₁ point H practice radius ratio Reduced Levels refraction represent right angles slope spirit-level stones subtracted superelevation surveyor Tables tangent telescope theodolite tion Top of bank Treatise turnpike road yards

### Popular passages

Page 27 - A Treatise on the Metallurgy of Iron : Containing Outlines of the History of Iron Manufacture, Methods of Assay, and Analysis of Iron Ores, Processes of Manufacture of Iron and Steel, etc., etc.

Page 25 - TUNNER (PA). Treatise on Roll-Turning for the Manufacture of Iron. Translated and adapted by John B. Pearse, of the Pennsylvania Steel Works, with numerous engravings, wood-cuts.

Page 24 - ROEBLING (JA) Long and Short Span Railway Bridges. By John A. Roebling, CE Illustrated with large copperplate engravings of plans and views.

Page 25 - Schools, in which the Definitions and Rules of Geometry are familiarly explained ; the Practical Problems are arranged, from the most simple to the more complex, and in their description technicalities are avoided as much as possible. With illustrations for Drawing Plans, Sections, and Elevations of Buildings and Machinery ; an Introduction to Isometrical Drawing, and an Essay on Linear Perspective and Shadows. Illustrated with over 200 diagrams engraved on steel.

Page 30 - APPLICATION OF THE SLIDE VALVE and Link Motion to Stationary, Portable, Locomotive and Marine Engines, with new and simple methods for proportioning the parts. By WILLIAM S. AUCHINCLOSS, Civil and Mechanical Engineer.

Page 30 - THE POWER OF WATER, as applied to drive Flour Mills, and to give motion to Turbines and other Hydrostatic Engines.

Page 30 - , Formula & Diagrams for Calculation of. A HANDY BOOK for the CALCULATION of STRAINS in GIRDERS and SIMILAR STRUCTURES, and their STRENGTH ; consisting of Formulas and Corresponding Diagrams, with numerous Details for Practical Application, &c.

Page 24 - Railway Practice American and European Railway Practice in the economical Generation of Steam, including the Materials and Construction of Coal-burning Boilers, Combustion, the Variable Blast...

Page 28 - W.) New method of correcting Lunar Distances, and improved method of finding the error and rate of a chronometer, by equal altitudes, 8vu, cloth 2 oo CHURCH (JOHN A.) Notes of a Metallurgical Journey in Europe.

Page 25 - Mechanical Drawing. A Text-book of Geometrical Drawing for the use of Mechanics and Schools, in w.hich the Definitions and Rules of Geometry are familiarly explained; the Practical Problems are arranged from the most simple to the more complex, and in their description technicalities are avoided as much as possible. With illustrations for drawing Plans, Sections, and Elevations of Railways...