## A Treatise of Practical Surveying: Which is Demonstrated from Its First Principles ... |

### Dentro del libro

Resultados 1-5 de 5

Página 261

E. Required the variation . True azimuth Magnetical azimuth N. 83o . 20 E S. 70.

30 E. Variation 12. 50 E. The true azimuth being to the right of the magnetical ...

**Suppose**the sun's true azimuth N. 830. 20. E. but the magnetical one N. 70 ° 30.E. Required the variation . True azimuth Magnetical azimuth N. 83o . 20 E S. 70.

30 E. Variation 12. 50 E. The true azimuth being to the right of the magnetical ...

Página 277

5 The plot ABCDEFGHA is proposed to be divided , geometrically , in the

proportion of 2 to 3 , by a right line from a given point in any boundary or angle

thereof ,

taught ...

5 The plot ABCDEFGHA is proposed to be divided , geometrically , in the

proportion of 2 to 3 , by a right line from a given point in any boundary or angle

thereof ,

**suppose**the point D. Reduce the plot to the triangle cDe , as alreadytaught ...

Página 286

feet out of the level , for the distance of 8 or 10 chains length , and

AB ( fig . 3. ) and find the middle between A and B , which

the instrument at C : direct the tube to a station - staff , held up at A , and elevate ...

feet out of the level , for the distance of 8 or 10 chains length , and

**suppose**it beAB ( fig . 3. ) and find the middle between A and B , which

**suppose**to be C ; plantthe instrument at C : direct the tube to a station - staff , held up at A , and elevate ...

Página 287

and observe the heights on the station - staves , which

and consequently their difference , as before , is 3 feet 0.6 inches . Now measure

from C towards the highest ground A , some distance that comes almost to A ...

and observe the heights on the station - staves , which

**suppose**to be as above ;and consequently their difference , as before , is 3 feet 0.6 inches . Now measure

from C towards the highest ground A , some distance that comes almost to A ...

Página 288

Or it will be still better to set the station staves , equally distant from the instrument

(

form nearly an equilateral triangle therewith , and level the 2 vanes ( A and B fig .

Or it will be still better to set the station staves , equally distant from the instrument

(

**suppose**about 16 or 20 perches each ) at an angle of about 60 ° or so as toform nearly an equilateral triangle therewith , and level the 2 vanes ( A and B fig .

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### Términos y frases comunes

acres angle Answer base bearing called centre chains chord circle Co-sec Co-sine Co-tang column contained decimal difference direct distance divided division draw drawn east edge equal EXAMPLE feet field field-book figures four four-pole fourth give given greater ground half height Hence inches laid land Lat Dep length less logarithm manner measure method multiplied needle object observe opposite parallel perches perpendicular plain plane Plate pole prob PROBLEM proportion quantity quotient radius reduce remainder right angles right line root scale Secant sect side sights sine square station suppose survey taken Tang tangent theo THEOREM third triangle triangle ABC true turn variation whence whole

### Pasajes populares

Página 25 - The circumference of every circle is supposed to be divided into 360 equal parts, called degrees ; and each degree into 60 equal parts, called minutes ; and each minute into 60 equal parts, called seconds ; and these into thirds, &c.

Página 207 - ... that triangles on the same base and between the same parallels are equal...

Página 40 - The angle in a semicircle is a right angle ; the angle in a segment greater than a semicircle is less than a right angle ; and the angle in a segment less than a semicircle is greater than a right angle.

Página 43 - Triangles upon equal bases, and between the same parallels, are equal to one another.

Página 103 - TO THEIR DIFFERENCE ; So IS THE TANGENT OF HALF THE SUM OF THE OPPOSITE ANGLES', To THE TANGENT OF HALF THEIR DIFFERENCE.

Página 31 - Figures which consist of more than four sides are called polygons ; if the sides are all equal to each other, they are called regular polygons. They sometimes are named from the number of. their sides, as a five-sided figure is called a pentagon, one of six sides a hexagon, &"c.

Página 31 - ... they are called regular polygons. They sometimes are named from the number of their sides, as a five-sided figure is called a pentagon, one of. six sides a hexagon, &c. but if their sides are not equal to each other, then they are called irregular polygons, as an irregular pentagon, hexagon, &c.

Página 45 - The hypothenuse of a right-angled triangle may be found by having the other two sides ; thus, the square root of the sum of the squares of the base and perpendicular, will be the hypothenuse. Cor. 2. Having the hypothenuse and one side given to find the other; the square root of the difference of the squares of the hypothenuse and given side will be the required side.

Página 265 - As the length of the whole line, Is to 57.3 Degrees,* So is the said distance, To the difference of Variation required. EXAMPLE. Suppose it be required to run a line which some years ago bore N. 45°.

Página 32 - Things that are equal to one and the same thing are equal to one another." " If equals be added to equals, the wholes are equal." " If equals be taken from equals, the remainders are equal.