A Manual for Practical Surveyors: Containing Methods Indispensably Necessary for Actual Field Operations |
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Page 12
... may be carried to about 20 ° . The links to be deducted , for every chain length oblique measure , to reduce it to horizontal measure , may also be marked on the sights , corresponding with the 12 A MANUAL FOR SURVEYORS .
... may be carried to about 20 ° . The links to be deducted , for every chain length oblique measure , to reduce it to horizontal measure , may also be marked on the sights , corresponding with the 12 A MANUAL FOR SURVEYORS .
Page 13
... horizontal line . Horizontal angles may be measured with the nonius compass . For this purpose , procure an extra pair of sights , made so as to be attached to the face or movable part of the instrument con- taining the needle , and at ...
... horizontal line . Horizontal angles may be measured with the nonius compass . For this purpose , procure an extra pair of sights , made so as to be attached to the face or movable part of the instrument con- taining the needle , and at ...
Page 15
... horizontal angles , is formed with two circular plates , the lower of which is firmly attached to the stem of the instrument , and may therefore be clamped to the tripod which supports it ; the upper plate is connected with the sights ...
... horizontal angles , is formed with two circular plates , the lower of which is firmly attached to the stem of the instrument , and may therefore be clamped to the tripod which supports it ; the upper plate is connected with the sights ...
Page 16
... horizontal measure . " It is generally recommended , when the compass is not in use , to place it in its box , where it will not be disturbed , and let the needle settle , and remain on its centre pin . However , I believe it preferable ...
... horizontal measure . " It is generally recommended , when the compass is not in use , to place it in its box , where it will not be disturbed , and let the needle settle , and remain on its centre pin . However , I believe it preferable ...
Page 67
... horizontal distance A B through a precipice or clift too steep to be mea- sured with the chain . Plant a staff at C on the top of A the cliff , aligning it with A and B , both of which may be seen from C. Run the line A E and measure it ...
... horizontal distance A B through a precipice or clift too steep to be mea- sured with the chain . Plant a staff at C on the top of A the cliff , aligning it with A and B , both of which may be seen from C. Run the line A E and measure it ...
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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.