Elements of Surveying and Leveling |
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Page 148
... limb . The vernier may be applied to any limb or scale of equal parts . The modes of its application are extremely various ; the principle , however , is the same in all , and may be illustrated by a simple diagram ( Fig . 83 ) . A 8 Ꮽ ...
... limb . The vernier may be applied to any limb or scale of equal parts . The modes of its application are extremely various ; the principle , however , is the same in all , and may be illustrated by a simple diagram ( Fig . 83 ) . A 8 Ꮽ ...
Page 149
... limb begins , marked 0 , to the 0 point of the vernier . In the diagram , that distance is expressed by nine units of the limb , or 9 . If , now , the vernier be moved till the division 1 coincides with the division 10 of the limb , the ...
... limb begins , marked 0 , to the 0 point of the vernier . In the diagram , that distance is expressed by nine units of the limb , or 9 . If , now , the vernier be moved till the division 1 coincides with the division 10 of the limb , the ...
Page 154
... limb of the instrument . Fitted to the upper conical surface of the main socket is a second socket to which is united a thin circular plate , AA , called the Vernier Plate , B L L B FIG . 86 . 178. The. 154 [ BOOK IV . ELEMENTS OF ...
... limb of the instrument . Fitted to the upper conical surface of the main socket is a second socket to which is united a thin circular plate , AA , called the Vernier Plate , B L L B FIG . 86 . 178. The. 154 [ BOOK IV . ELEMENTS OF ...
Page 155
... limb BB is attached to the main socket of LL , which is itself carefully fitted to the conical spindle P , and held in place by the spring catch C. The upper plate , AA , carrying the compass - circle , standards , & c . , is fastened ...
... limb BB is attached to the main socket of LL , which is itself carefully fitted to the conical spindle P , and held in place by the spring catch C. The upper plate , AA , carrying the compass - circle , standards , & c . , is fastened ...
Page 156
... limb of the instrument is prevented from revolving . One of the tangent screws I , being then loosened as the other is tightened , will slowly and steadily move the clamp- ring itself and with it , of course , the limb . The limb , BB ...
... limb of the instrument is prevented from revolving . One of the tangent screws I , being then loosened as the other is tightened , will slowly and steadily move the clamp- ring itself and with it , of course , the limb . The limb , BB ...
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Common terms and phrases
adjusted axis azimuth base-line bearing centre chain chord clamp column corresponding Cosine Cosine D Cotang course cross-wires curve declination arc degree of curvature degrees determined difference of level direction divided draw east equal equatorial lines error example feet given ground hence horizontal distance horizontal line inches intersection latitude and departure length limb logarithm magnetic magnetic bearing magnetic declination main socket mantissa marked measured method needle notes observation offsets parallel perpendicular plane plane of reference plot plumb-bob position protractor radius reading revolve right angles scale screws sextant shaft side sight Sine slope Solar Compass stakes station straight line subtracted surface survey surveyor taken Tang tangent points tangent-screw telescope tion transit trapezoids traverse triangle true meridian tunnel vernier plate vertical zero
Popular passages
Page 18 - 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, fourths, &c.
Page 7 - The location must be distinctly marked on the ground so that its boundaries can be readily traced. All records of mining claims hereafter made shall contain the name or names of the locators, the date of the location, and such a description of the claim or claims located by reference to some natural object or permanent monument as will identify the claim.
Page 94 - IL + .VC; hence, the double meridian distance of a course is equal to the double meridian distance of the preceding course, plus the departure of that course, plus the departure of the course itself: if there is no preceding course, the first two terms become zero.
Page 373 - The declination of the sun, given in the Ephemeris of the Nautical Almanac, from year to year, is calculated for apparent noon at Greenwich, England. To determine it for any other hour at a place in the...
Page 1 - Caution as to the False Image. In using the compass upon the sun, if the revolving arm be turned a little one side of its proper position, a false or reflected image of the sun will appear on the silver plate in nearly the same place as that occupied by the true one. It is caused by the reflection of the true image from the surface of the arm, and is a fruitful source of error to the inexperienced surveyor. It can, however, be readily distinguished from the real image by being much less bright, and...
Page 25 - 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 9 - 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 141 - ... being about three feet above the surface, and the posts about four feet apart: then lay a plank, or piece of timber three or four inches in width, and smooth on the upper side, upon the posts, and let it be pinned or nailed, to hold it firmly. 2. Prepare a piece of board four or five inches square, and smooth on the under side. Let one of the compass-sights be placed at right angles to the upper surface of the board, and let a nail be driven through the board, so that it can be tacked to the...
Page 373 - Territory about eight hours. Having thus the difference of time, we very readily obtain the declination for a certain hour in the morning, which would be earlier or later as the longitude was greater or less, and the same as that of apparent noon at Greenwich on the given day. Thus, suppose the observation made at a place...
Page 168 - Let this board be so fixed to a vertical staff as to slide up and down freely; and let a small piece of board, about three inches square, be nailed to the lower edge of it, for the purpose of holding a candle. About twenty-five minutes before the time of the greatest eastern or western elongation of the pole-star, as shown by the tables of elongations, let the theodolite be placed at a convenient point and leveled.