A Manual for Practical Surveyors: Containing Methods Indispensably Necessary for Actual Field Operations |
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Page 16
... let the needle settle , and remain on its centre pin . However , I believe it preferable to let the needle settle , and then carefully screw it up or off the centre pin ; it will then be very nearly in the magnetic meridian , and will ...
... let the needle settle , and remain on its centre pin . However , I believe it preferable to let the needle settle , and then carefully screw it up or off the centre pin ; it will then be very nearly in the magnetic meridian , and will ...
Page 25
... Let the needle down on the centre pin , and take the bearing of the line , screw up the needle carefully ; next remove the in- strument to B , set the needle to the course of A B and run to C , and from thence to D , and so on as far as ...
... Let the needle down on the centre pin , and take the bearing of the line , screw up the needle carefully ; next remove the in- strument to B , set the needle to the course of A B and run to C , and from thence to D , and so on as far as ...
Page 60
... needle on the several lines . B A Set the instrument at A , direct a stake to be set at B , let the needle down on its centre pin , and direct the sights to B. If the needle does not show the same bearing as formerly , move the vernier ...
... needle on the several lines . B A Set the instrument at A , direct a stake to be set at B , let the needle down on its centre pin , and direct the sights to B. If the needle does not show the same bearing as formerly , move the vernier ...
Page 79
... may throw the line EF a pole from its true position in many cases that occur in practice . PROPOSITION 11 . To ... Let ABCD be several sides of B a survey on which the needle is disturbed by some extraneous mat- ter . X A D With ...
... may throw the line EF a pole from its true position in many cases that occur in practice . PROPOSITION 11 . To ... Let ABCD be several sides of B a survey on which the needle is disturbed by some extraneous mat- ter . X A D With ...
Page 86
... may be de- sired to be run out or retraced , it may be proper here to give an example embracing a number of those cases ... let the needle down upon the centre - pin , revolve the instrument B احات KKK n m E A so as to 86 A MANUAL FOR ...
... may be de- sired to be run out or retraced , it may be proper here to give an example embracing a number of those cases ... let the needle down upon the centre - pin , revolve the instrument B احات KKK n m E A so as to 86 A MANUAL FOR ...
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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.