## A Treatise on Land-surveying: Comprising the Theory Developed from Five Elementary Principles; and the Practice with the Chain Alone, the Compass, the Transit, the Theodolite, the Plane Table, &c. : Illustrated by Four Hundred Engravings, and a Magnetic ChartD. Appleton & Company, 1857 - 524 pages |

### From inside the book

Results 6-10 of 54

Page 139

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**West**; if at G , N. 60 ° W ; if at H , North . B90 Fig . 163 . H D G W90F 15 ° ( 236 ) We can now understand why W is or . the right hand of the compass - box , and E on the left . Let the direction from the centre of the compass to the ... Page 147

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**West**point , and the difference between this sum and 180 ° will be the new bearing and the first letter will be changed , N. being put for S. and S. for N. Example . Let the Bearings of the sides of a field be as follows : N. 32 ° E ... Page 162

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**West**lines . The long side of the protractor will then be on a meridian and the proper angle ( 40 ° in the figure ) can be at once marked off . The length of the course can also be set off by the equal spaces between the cross - lines ... Page 163

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**West**lines . Any course of the survey will be the hypothenuse of a right - angled triangle , and the ratio of its other two sides will determine the angle . Thus , if the ratio of the two sides of the right - an- gled triangle , of ... Page 164

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**West**, makes likewise an angle of 14 ° with that side , and therefore makes an angle of 76 ° with the meridian . * To facilitate the use of this method , the following table has been prepared . TABLE FOR PLATTING BY SQUARES . Angle ...### Common terms and phrases

ABCD acres alidade axis base line calculated centre CHAPTER chord circle compass convenient corner correct course cross-hairs degrees desired desired line determined diagonal difference direction distance divided division Double Longitude draw drawn East edge equal error feet field Field-notes figure fixed gamboge given line given point ground half horizontal inaccessible inch India ink instrument intersection Latitudes and Departures length line of sight Magnetic MAGNETIC BEARING marked Meridian method move needle North Star object observed obtained offsets paper parallel pass perpendicular plane plat plate plumb-line preceding precisely prolonged protractor quadrilateral radius reading represent right angles scale screws side similar triangles sine South square chains station straight line subtract survey surveyor Table telescope Theodolite tion township Transit trapezoid Trigonometry true North turn Variation Vernier Vernier scale vertical West

### Popular passages

Page 153 - All the interior angles of any rectilineal figure, together with four right angles, are equal to twice as many right angles as the figure has sides.

Page 379 - Every circumference is regarded as being divided into 360 equal parts, called degrees. Each degree is divided into 60 equal parts, called minutes, and each minute into 60 seconds. These divisions are indicated by the marks ° ' ". Thus 28 degrees, 17 minutes, and 49 seconds, are written 28° 17

Page 364 - ... shall be specially noted, and added to or deducted from the western or northern ranges of sections or half-sections in such township, according as the error may be in running the lines from east to...

Page 313 - If foot for each degree of Fahrenheit. If a wind blows with or against the movement of the sound, its velocity must be added or subtracted. If it blows obliquely, the correction will evidently equal its velocity multiplied by the cosine of the angle which the direction of the wind makes with the direction of the sound.* If the gun be fired at each end of the base in turn, and the means of the times taken, the effect of the wind -will be eliminated. If a watch is not at hand, suspend a pebble to a...

Page 370 - President may prescribe, to cause the lands thus situated to be surveyed in tracts of two acres in width, fronting on any river, bayou, lake, or watercourse, and running back the depth of forty acres...

Page 267 - heliotrope," which is a piece of looking-glass, so adjusted as to reflect the sun directly to any desired point, is the most perfect arrangement. For night signals, an Argand lamp is used ; or, best of all, Drummond's light, produced by a stream of oxygen gas directed through a flame of alcohol upon a ball of lime. Its distinctness is exceedingly increased by a parabolic reflector behind it, or a lens in front of it. Such a light was brilliantly visible at 66 miles distance.

Page 372 - The precise relative position of islands, in a township made fractional by the river in which the same are situated, is to be determined trigonometrically — sighting to a flag or other fixed object on the island, from a special and carefully measured base line, connected with the surveyed lines, on or near the river bank, you are to form connection between the meander corners on the river to points corresponding thereto, in direct line, on the bank of the island, and there establish the proper...

Page 155 - When the bounds are given by compass-bearings, the surveyor must be reminded that these bearings are very far from being the same now as originally, having been changing every year. The method of determining this important change, and of making the proper allowance, will be found in Chapter VIII, of this Part. (261) Town Surveying, Begin at the meeting of two or more of the principal streets, through which you can have the longest prospects. Having fixed the instrument at that point, and taken the...

Page 376 - BASE lines, showing the establishment of the township, section or mile, and quarter.section or half.mile, boundary corners thereon ; with the crossings of streams, ravines, hills, and mountains ; character of soil, timber, minerals, &c. These notes will be arranged, in series, by mile stations, from number one to number . 2. Field.notes of the ' STANDARD PARALLELS, or correction lines...

Page 366 - ... (either of which would indicate an important error in the surveying,) the lines must be retraced, even if found necessary to remeasure the meridional boundaries of the township, (especially the western boundary,) so as to discover and correct the error ; in doing which, the true corners must be established and marked, and the false ones destroyed and obliterated to prevent confusion in future ; and all the facts must be distinctly