# A Compendious System of Practical Surveying, and Dividing of Land: Concisely Defined, Methodically Arranged, and Fully Exemplified : the Whole Adapted for the Easy and Regular Instruction of Youth, in Our American Schools

Johnson and Warner, 1814 - 227 sider

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### Innhold

 SURVEYING Page 1 Projection of the Lines Sines Tangents and Secants 40 Of flogarithms 51 Trigonometry 63 Oblique Angled Trigonometry 81 Heights 90 Distances 100 To make a Map from the Field Notes 120
 Demonstration 137 Inaccessible Boundary 146 Pennsylvania method of calculation 155 OffSets 163 Division of Land 172 Intersections 198 Attraction 211 To find the variation of compass by an amplitude 217

### Populære avsnitt

Side 50 - ЙО, 30, &c., to the left hand, where it ends at 87 degrees. This line. with the line of equal parts, marked (EP), under it, are used together, and only in Mercator's Sailing. The upper line contains the degrees of the meridian, or latitude in a Mercator's chart, corresponding to the degrees of longitude on the lower line. The use of this Scale in solving the usual problems of Trigonometry...
Side 80 - To the length of the given side ; So is the sine of the angle opposite the required side. To the length of the required side.
Side 4 - 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, etc.
Side 44 - I tenth part ; and the next 2, 2 tenth parts; and 10 at the end will be but one whole number or integer. As the figures are increased or diminished in their value, so in like manner must all the intermediate strokes or subdivisions be increased or diminished ; that is, if the first...
Side 47 - EXAMPLE. If the diameter of a circle be 7 inches, and the circumference 22, what is the circumference of another circle, the diameter of which is 14 inches ? Extend from 7 to 22, that extent will reach from 14 to 44 the same way.
Side 217 - Then if the true and magnetic amplitudes be both north or both south their difference is the variation, but if one be north and the other south their sum is the variation ; and to know whether it be easterly or westerly, suppose the observer looking towards that point of the compass representing the magnetic amplitude; then if the true amplitude be to the...
Side 220 - Ъои) on the east, or both on the west side of the meridian, their difference is the variation : but if one be on the east, and the other on the west side of the meridian, their sum is the variation ; and to know if it be east or west, suppose the observer looking towards that point of the compass representing the magnetic azimuth ; then if the true •azimuth be to the right of the magnetic, the variation is east, but if the true be to the left of the magnetic, the variation is west. EXAMPLE....
Side 215 - 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.
Side 219 - . 2. Subtract the Sun's declination from 90«, when the latitude and declination are of the same name, or add it to 90*, when they are of contrary names ; and the sum, or remainder, will be the Sun's polar distance. , 3. Add together the Sun's polar distance, the latitude of the place, and the altitude of the Sun; take the difference between half their sum and the polar distance, and note the remainder.
Side 49 - ... degrees of the quadrant, begins at the right hand against 90° on the sines, and from thence is numbered towards the left hand thus : 10, 20...