Field and Colliery Surveying: A Primer Designed for the Use of Students of Surveying and Colliery Manager AspirantsMacmillan & Company, 1911 - 263 páginas |
Dentro del libro
Resultados 1-5 de 27
Página 37
... approximately the sin of 22 ° . ... angle C = 22 ° , and the angle A = 180 ° – ( 30 ° + 22 ° ) = 128 ° . Now 128 ° is greater than a right angle ; to find the sine of 128 ° subtract it from 180 ° , and find the sine of the remainder ...
... approximately the sin of 22 ° . ... angle C = 22 ° , and the angle A = 180 ° – ( 30 ° + 22 ° ) = 128 ° . Now 128 ° is greater than a right angle ; to find the sine of 128 ° subtract it from 180 ° , and find the sine of the remainder ...
Página 38
... approximately correct , as the sines do not increase in the same ratio as the angles . Nevertheless fairly accurate results may be obtained in this way . To minimise the error due to proportioning , the nearest tabular value should be ...
... approximately correct , as the sines do not increase in the same ratio as the angles . Nevertheless fairly accurate results may be obtained in this way . To minimise the error due to proportioning , the nearest tabular value should be ...
Página 40
... tan of angle Perpendicular Base = 20 50 4 is approximately the tan of 21 ° 48 ′ .. the inclination of the dumb drift = 21 ° 48 ' . CHAPTER VI MEASUREMENTS Units of Measurement . — To measure 40 CHAP . V COLLIERY SURVEYING.
... tan of angle Perpendicular Base = 20 50 4 is approximately the tan of 21 ° 48 ′ .. the inclination of the dumb drift = 21 ° 48 ' . CHAPTER VI MEASUREMENTS Units of Measurement . — To measure 40 CHAP . V COLLIERY SURVEYING.
Página 46
... approximately the line ; an assistant places a staff at C ' in line with A and B ' , and the surveyor at B ' then sees that the line he has staffed out will when produced pass to the left of D. The surveyor therefore moves the staff B ...
... approximately the line ; an assistant places a staff at C ' in line with A and B ' , and the surveyor at B ' then sees that the line he has staffed out will when produced pass to the left of D. The surveyor therefore moves the staff B ...
Página 51
... approximately correct up to 45 degrees : — Square the number of degrees , multiply by 1 and cut off the two last figures as decimals , which is practically the same as dividing by 100 . EXAMPLES.- 6 06 links per chain to be deducted , 2 ...
... approximately correct up to 45 degrees : — Square the number of degrees , multiply by 1 and cut off the two last figures as decimals , which is practically the same as dividing by 100 . EXAMPLES.- 6 06 links per chain to be deducted , 2 ...
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.