Engineering Field Notes on Parish and Railway Surveying and Levelling, with Plans and Sections, Being a Sequel to His Elementary Text Book: With Practical Formula@ for the Calculation of Earth-work, the Theory and Practice of Running Out Curves and Putting Down Side Stakes, Etc., and a Traverse Table |
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Engineering Field Notes on Parish and Railway Surveying and Levelling, with ... Henry James Castle No preview available - 2018 |
Engineering Field Notes On Parish and Railway Surveying and Levelling, With ... Henry James Castle No preview available - 2023 |
Engineering Field Notes On Parish and Railway Surveying and Levelling, With ... Henry James Castle No preview available - 2023 |
Common terms and phrases
angles of elevation angles taken backset base line broad arrow bubble calculated centre chains long CHAP check line Circumferentor collimation column corner correct cosec cross hedges curve departure determined difference direction ditch east embankment equal error example feet field book field notes flag foreset given gradient ground Hampstead height Highgate Church horizontal instrument intersection Knockholt latitude length line crosses line measured loose line meridian line method miles Mordiford multiplier needle Newton Harcourt object observation obtained offsets parish perpendicular plate plotting pole star portion position practice radius railway surveying reading reduced levels road screws Sextant side sine slopes spherical excess spirit level staff stakes station Streatham sun's surveyor take the angle tangent telescope theodolite triangle vernier vertical whole width Wigston zenith distance
Popular passages
Page 62 - ... the object, and the intersection of the wires, clearly and sharply defined, before it. The existence of parallax is very inconvenient, and, where disregarded, has frequently been productive of serious error. It will not always be found sufficient to set the eye-glass first, and the object-glass afterwards. The setting of the object-glass, by introducing more distant rays of light, will affect the focus of the eye-glass, and produce parallax or indistinctness of the wires, when there was none...
Page 165 - LEVELLING is the art of representing the inequalities of the earth's surface, and of determining the relative heights of any number of points above or below a line, equidistant, at every point, from the centre of the earth.
Page 63 - ... frequently been productive of serious error. It will not always be found sufficient to set the eye-glass first, and the object-glass afterwards. The setting of the object-glass, by introducing more distant rays of light, will affect the focus of the eye-glass, and produce parallax or indistinctness of the wires, when there was none before. The eye-piece must, in this case, be adjusted again. Generally, when once set for the day, there is no occasion for altering the eye-glass, but the object-glass...
Page 57 - Extend the three legs, approaching or extending each, until the bubbles in the two levels (BB) are nearly central, and the plummet, suspended from a hook under the body of the instrument, hangs freely above the centre of the station. The better plan is to move only one leg, which is, of itself, capable of a double motion. Press the legs firmly in the ground, unclamp the whole instrument by means of the large clamp-screw (C,) observing to keep the other motions clamped. It must now be remembered,...
Page 115 - ... which has been observed on making trigonometrical observations on a large scale. "The angles taken between any three points on the surface of the earth by the theodolite are, strictly speaking, spherical angles, and their sum must exceed 180 degrees; and the lines bounding them are not the chords as they should be, but the tangents to the earth. This excess is inappreciable in common cases, but in the larger triangles it becomes necessary to allow for it, and to diminish each of the angles of...
Page 179 - C, will give the actual fall perpendicularly from A to D ; in the same way the rise from D to F is estimated : if, therefore, the fall from A to D be greater than the rise from D to F, the difference of these two will be the actual fall from AF, or the distance in feet estimated perpendicularly, that the station A is higher than the station F.
Page 151 - N..Ol^W. 26.47 16.56 20.65 52.70 52.70 .06.72 56.72 2. Given the bearings and distances of the sides of a tract of land, as follow: 1st.
Page 60 - ... perfectly level, when the zero point of the circle and the broad arrow are together, raise or depress the telescope, till you distinctly cut the required object with the horizontal wire, or the common intersection of the three wires. The changed relative position of the broad arrow, will give the required angle, which will be an angle of depression, if the broad arrow be found between the zero of the vertical arc and the object-glass of the telescope, and of elevation, if beyond them.
Page 18 - This must always be the plan adopted in the survey of a village, or farmhouse, or homestead ; to confine all the areas within one triangle, whose three sides should severally pass through the principal points of the place. Having given the method, adopted in practice, for saving time in the survey of the plan, we will proceed to explain the nature and use of the several main lines. The line ME, of the triangle DME, is the measure of the angle MDE: but CH, in the triangle CUD, is the measure of the...
Page 62 - Let one bubble be over one pair of the circular plate screw, then the other bubble will be over the conjugate pair; make both bubbles level, turn them half round the circumference, and if the bubbles deviate from the centre, correct one half the error, by the small milled-headed screws above the levels: and the other half error, by the circular plate screws ; repeat this, till the bubbles are level, in every position, throughout a whole revolution of the circumference. HORIZONTAL. 2. Whether after...