## 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 |

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

### Popular passages

Page 151 - 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 182 - Hast or West Station, and place them in the eighth column. 5. Multiply the Double Longitude of each course by the corrected Latitude of that course, placing the North Products in the ninth column, and the South Products in the tenth column. 6. Add up the last two columns, subtract the smaller sum from the larger, and divide the difference by two. The quotient will be the content desired.

Page 368 - 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 133 - C is a prism which the observer looks through. The perpendicular thread of the sight.vane, E, and the divisions on the card appear together on looking through the prism, and the division with which the thread coincides when the needle is at rest, is the

Page 370 - 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 167 - Definitions. The LATITUDE of a point is its distance North or South of some " Parallel of Latitude" or line running East or West. The LONGITUDE of a point is its distance East or West of some "Meridian" or line running North and South.

Page 370 - A sufficient number of other trees standing within 50 links of the line, on either side of it, are to be blazed on two sides diagonally, or quartering toward the line, in order to render the line conspicuous, and readily to be traced, the blazes to be opposite each other, coinciding in direction with the line where the trees stand very near it, and to approach nearer each other the farther the line passes from the blazed trees. Due care must ever be taken to have the lines so well marked as to be...

Page 153 - ... 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 bearings of all the streets issuing from it, measure all these...

Page 364 - The principal meridian, tho base line, and the standard parallels having been first astronomically run, measured, and marked, according to instructions, on true meridians, and true parallels of latitude, the process of running, measuring, and marking the exterior lines of townships will be as follows. Townships situated NORTH of the base line, and WEST of the principal meridian* Commence at No.

Page 136 - Bearing and length of a line are named collectively the Course. To take the Bearing of any line, set the compass exactly over any point of it by a plumb-line suspended from beneath the centre of the compass, or, approximately, by dropping a stone. Level the compass by bringing the air bubbles to the middle of the level tubes.