## 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 TableD. Appleton and Company, 1855 - 524 pages |

### From inside the book

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Page 109

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**screw**, S , holds the disc in a slit in the top of the pole . Another contrivance is a strip of tin , which has its ends bent horizontally in contrary directions . As the wind will take strong- est hold of the side which is concave ... Page 111

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**screws**by which the mirror KL may be adjusted . The distance between the two tubes will cause a small parallax , which will , however , be insensible except when the two objects are near together . ( 183 ) Through a Wood . When a wood ... Page 128

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**screw**, with a milled head , on the under side of the plate which supports the pivot , is used to raise the needle off this pivot , when the instrument is carried about , to prevent the point being dulled by unnecessary friction . ( 222 ) ... Page 132

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**screw**, ( called a slow - mo- tion , or Tangent**screw**) , the head of which is the nearest one in the figure on page 126. If two marks be made 132 [ PART III . COMPASS SURVEYING . Page 133

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**screw**is turned . Their distance apart ( in angular measurement , i . e . fractions of a circle ) , in any posi- tion , is measured by a contrivance called a Vernier , which is the minutely divided arc of a circle seen between the left ...### Other editions - View all

### Common terms and phrases

ABCD acre alidade Bearing calculated centre Chapter circle compass convenient corner correct course cross-hairs desired desired line determined diagonal difference direction distance divided division draw drawn East equal feet field Field-notes figure fixed gamboge given line given point half horizontal inch India ink instrument intersection Latitudes and Departures length line of sight MAGNETIC BEARING marked Meridian method mile multiply needle 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 stake station straight line subtract survey surveyor Table telescope Theodolite Theorem tion township Transit trapezoid Trigonometry true North turn Variation Vernier Vernier scale vertical West whence བ བ བ

### 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 of a. circle, whether the circle be large or small, is supposed to be divided into 360 equal parts called degrees. Each degree is divided into 60 equal parts called minutes, and each minute into 60 equal parts called seconds.

Page 365 - ... in all cases where the exterior lines of the townships thus to be subdivided into sections or half sections, shall exceed, or shall not extend six miles, the excess or deficiency 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 west, or from south to north...

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 169 - Longitudes of points are measured, or reckoned. The distance which one end of a line is due North or South of the other end, is called the Difference of Latitude of the two ends of the line ; or its Nortldng or Southing ; or simply its Latitude.

Page 267 - ... Captain Kater. By means of this a station 48 miles distant was observed. The most powerful night signal is, however, Drummond's light. This was invented by Lieutenant Drummond, and consists of a ball of lime about \ in. diameter placed in the focus of a parabolic reflector and raised to an intense heat by a stream of oxygen gas directed through a flame of alcohol. This produces a light eighty times the intensity of an Argand burner. In boisterous and hazy weather this light was brilliantly visible...

Page 367 - E., and proceed as with townships situated " north and wrest," except that the random or trial lines will be run and measured west, and the true lines, east, throwing the excess over or deficiency under four hundred and eighty chains on the west end of the line, as required by law ; wherefore, the surveyor will commence his measurement with...

Page 372 - 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 44 - The content of a Trapezoid equals half the product of the sum of the parallel sides by the perpendicular distance between them.

Page 375 - Prior to piling up the earth to construct a mound, in a cavity formed at the corner boundary point is to be deposited a stone, or a portion of charcoal, or a charred stake is to be driven twelve inches down into such centre point, to be a witness for the future.