Field and Colliery Surveying: A Primer Designed for the Use of Students of Surveying and Colliery Manager AspirantsMacmillan & Company, 1911 - 263 páginas |
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Página 92
... necessary to have the instrument perfectly horizontal if the angle of inclination or dip has to be taken , or errors will result . If the socket joint of the legs moves too easily or is too stiff , a turn of 92 CHAP . COLLIERY SURVEYING.
... necessary to have the instrument perfectly horizontal if the angle of inclination or dip has to be taken , or errors will result . If the socket joint of the legs moves too easily or is too stiff , a turn of 92 CHAP . COLLIERY SURVEYING.
Página 93
... legs by means of the screw . The needle having settled , the bearing , as indicated by the north end of the needle , is read off from the circle , which is graduated in quadrants , each reading from 0 to 90. If the north end of the ...
... legs by means of the screw . The needle having settled , the bearing , as indicated by the north end of the needle , is read off from the circle , which is graduated in quadrants , each reading from 0 to 90. If the north end of the ...
Página 94
... is perfectly straight , and that a light held in the centre of the shaft can be seen at A , the surveyor plants the legs of the dial at this point , having The previously seen that the iron , if any , 94 CHAP . COLLIERY SURVEYING.
... is perfectly straight , and that a light held in the centre of the shaft can be seen at A , the surveyor plants the legs of the dial at this point , having The previously seen that the iron , if any , 94 CHAP . COLLIERY SURVEYING.
Página 95
... legs of the dial should be so placed that a sight may also be taken along the road to B without having to remove them . The dial is then placed on the legs , the levelling adjustment made , the needle allowed to swing freely , and the ...
... legs of the dial should be so placed that a sight may also be taken along the road to B without having to remove them . The dial is then placed on the legs , the levelling adjustment made , the needle allowed to swing freely , and the ...
Página 96
... legs , that the light be held in exactly the same vertical line as in the previous observation . To ensure this being done , a small chalk mark should be made on the roof , and the sight lamp suspended by a cord held at the mark . When ...
... legs , that the light be held in exactly the same vertical line as in the previous observation . To ensure this being done , a small chalk mark should be made on the roof , and the sight lamp suspended by a cord held at the mark . When ...
Términos y frases comunes
accuracy accurate acres adjusted alidade ascertain back-sight calculated centre chain line chord clamped clinometer coal colliery column commences compass box contour lines datum line dial difference direction distance division drawing drawn dumpy level equal error example fast needle feet Field Book figure fixed fore-sight frustum graduated Gunter's chain height horizontal hypothenuse inch inclination instrument isogonic lines legs length limb magnetic bearing magnetic declination magnetic meridian magnetic needle marked means measurements meridian angle meridian base line meridian line method necessary needle survey observation obtained offsets parallel parallel ruler perpendicular placed plotted pricker protractor radius reduced level right angles road ruler scale screw seam shaft shown by Fig side sight line sight vanes spirit level square station straight line surveyor taken taking telescope theodolite tie line traverse triangle true north underground survey vernier plate vernier reading yards zero
Pasajes populares
Página 22 - To draw a straight line at right angles to a given straight line, from a given point in the same.
Página 164 - Triangles on the same base, and between the same parallels, are equal.
Página 19 - Any two sides of a triangle are together greater than the third side.
Página 249 - A section of the strata sunk through, or, if that is not reasonably " practicable, a statement of the depth of the shaft with a section
Página 248 - Every such plan must be on a scale of not less than that of the Ordnance Survey of twenty-five inches to the mile, or on the same scale as the plan for the time being in use at the mine.
Página 16 - A diameter of a circle is a straight line drawn through the centre, and terminated both ways by the circumference.
Página 19 - When the three angles of one are equal to the three angles of the other, each to each, the adjoining diagram shews that the triangles need not be equal in all respects.
Página 12 - A plane superficies is that in which any two points being taken, the straight line between them lies wholly in that superficies.
Página 21 - To bisect a given finite straight line, that is, to divide it into two equal parts. Let AB be the given straight line; it is required to divide it into two equal parts.
Página 34 - We have, then, that the sine of an angle is equal to the cosine of its complement, and conversely.