# Elements of Surveying, and Navigation: With Descriptions of the Instruments and the Necessary Tables

A. S. Barnes & Burr, 1862 - Navigation - 393 pages

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### Contents

 SECTION 1 9 Multiplication by Logarithms 15 PLANE SURVEYING 19 Geometrical Constructions 25 Gunters Scale 32 SECTION III 38 Theorems 44 Solution of RightAngled Triangles 54
 Offsets 122 SECTION IV 131 Variation of the Needle 134 1 137 The Y Level 147 Levelling in the Field 153 SECTION II 159 Field Notes 166 GEODESIC TRIGONOMETRIC AND MARITIME 172

 Measurement of Lines and Angles 66 Verniers 75 Surveying Cross 81 Of Laying out Land 96 Field Operations 102 Of Balancing the Work 109 Of Finding the Area 114
 Triangulation 178 To Measure a Horizontal Angle 185 Plotting the Triangulation 192 SECTION 201 SECTION III 207 SECTION V 214 Mercators Chart 221

### Popular passages

Page 42 - The circumference of every circle is supposed to be divided into 360 equal parts, called degrees...
Page 65 - Being on a horizontal plane, and wanting to ascertain the height of a tower, standing on the top of an inaccessible hill, there were measured, the angle of elevation of the top of the hill 40°, and of the top of the tower 51° ; then measuring in a direct line 180 feet farther from the hill, the angle of elevation of the top of the tower was 33° 45' ; required the height of the tower.
Page 115 - Longitude of the preceding course^ plus the Departure of that course, plus the Departure of the course itself* The Double Longitude of the last course (as well as of the first) is equal to its Departure. Its "coming out" so, when obtained by the above rule, proves the accuracy of the calculation of all the preceding Double Longitudes.
Page 13 - THE LOGARITHM: of a number is the exponent of the power to which it is necessary to raise a fixed number, to produce the given number.
Page 144 - Now, if the elongation, at the time of observation, was west, and the north end of the needle is on the west side of the line, the azimuth, plus the angle shown by the needle, is the true variation. But should the north end of the needle be found on the east side of the line, the elongation being west, the difference between the azimuth and the angle would show the variation, and the reverse when the elongation is east. 1. Elongation west, azimuth 2° 04' North end of the needle on the west, angle...
Page 96 - What must be the nominal value of 4% bonds that will yield to their owner an annual income of \$720 ? 7. A owns \$6000 of 5% bonds; B owns \$8000 of 4£% bonds. How much greater is the annual income from B's bonds than from A's ? 8. Find the area of a piece of land in the form of a rhomboid, whose base is 32 rods and whose altitude is 15 rods.
Page 144 - Then if the star depart from the plumb-line, move the compass-sight, east or west, along the timber, as the case may be, until the star shall attain its greatest elongation, when it will continue behind the plumb-line for several minutes ; and will then recede from it in the direction contrary to its motion before it became stationary. Let the compass-sight be now fastened to'the horizontal plank.
Page 26 - In a Right-angled Triangle, the side opposite the right angle is called the Hypothenuse ; and the other two sides are called the Legs, and sometimes the Base and Perpendicular.
Page 49 - C' (89) (90) (91) (92) (93) 112. In any plane triangle, the sum of any two sides is to their difference as the tangent of half the sum of the opposite angles is to the tangent of half their difference.
Page 43 - The secant of an arc is the line drawn from the centre of the circle through one extremity of the arc, and limited by the tangent passing through the other extremity. Thus, . 00 is the secant of the arc AB.