A Manual for Practical Surveyors: Containing Methods Indispensably Necessary for Actual Field Operations |
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Page 88
... needle . Unclamp the ver- nier plate and bring the telescope to bear on a third station C. Let the needle settle - suppose it reads N. 79 ° 55 ' E ; at the same time the vernier reads 79 ° 54 ' . In measuring this line B C , an obstacle ...
... needle . Unclamp the ver- nier plate and bring the telescope to bear on a third station C. Let the needle settle - suppose it reads N. 79 ° 55 ' E ; at the same time the vernier reads 79 ° 54 ' . In measuring this line B C , an obstacle ...
Page 90
... let the instrument be set for ob- serving the course of D E. The telescope being reversed and brought to bear on a back stake P , in the random line C q , the vernier at the same time reading 130 ° , let ... needle due west measuring 7 chains ...
... let the instrument be set for ob- serving the course of D E. The telescope being reversed and brought to bear on a back stake P , in the random line C q , the vernier at the same time reading 130 ° , let ... needle due west measuring 7 chains ...
Page 100
... Let the ordinates or offsets , at six equidistant places be 4 , 6 , 2 , 3 , 5 and 8 , the equi- distance apart being ... needle in causing uncertainty in retracing old lines of survey , is well known . A Al step towards obviating the ...
... Let the ordinates or offsets , at six equidistant places be 4 , 6 , 2 , 3 , 5 and 8 , the equi- distance apart being ... needle in causing uncertainty in retracing old lines of survey , is well known . A Al step towards obviating the ...
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Common terms and phrases
40 perches A E produced angles of deflection angular point back sight bearing of A B bring the sights bring the telescope centre pin circumferenter clamp the lower closing line correction course degrees difference of variation distance A C equal F B G feet Given A B internal angles kerfs last station let the needle line A B line C D line joining lines of survey lower plate magnetic magnetic bearings marked tree n¹ m¹ n³ m³ nier nonius compass nonius plate parallel perpendicular distance Place the instrument present bearing PROPOSITION quired random line right angles right line run a line run the line Set the instrument set the vernier sights to bear subtracted surveyor tance tang telescope to bear tion trapezoid traverse table tripod true bearing true line unclamp vernier to zero
Popular passages
Page 80 - All the interior angles of any rectilineal figure, together with four right angles, are equal to twice as many right angles as the figure has sides.
Page 17 - ... more than half through its thickness, and intersecting each other at right angles at the centre of the block...
Page 58 - A line which is to be established from the course only, should be re-run at nearly the same season...
Page 58 - It must, therefore, be a matter of uncertainty 'whether we have the correct bearing of the line, even when the change for years has been ascertained with the utmost care.
Page 57 - The variation of the magnetic needle in declination, is subject to much irregularity, in some instances increasing, in other decreasing, and some years having scarcely a perceptible motion.