A Manual for Practical Surveyors: Containing Methods Indispensably Necessary for Actual Field Operations |
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Page 15
... 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 , and moves with them . These circles are concen ...
... 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 , and moves with them . These circles are concen ...
Page 30
... lower plate to the tripod , unclamp the upper plate , and bring the telescope to bear on C a staff in the other line comprehending the required angle ; the vernier will point out the measure of the angle A B C. In this position clamp the ...
... lower plate to the tripod , unclamp the upper plate , and bring the telescope to bear on C a staff in the other line comprehending the required angle ; the vernier will point out the measure of the angle A B C. In this position clamp the ...
Page 31
... lower plate ; unclamp the upper plate , and bring the telescope to bear on C ; the vernier will show twice the angle A B C. We may repeat this operation at pleasure , the last reading of the vernier being divided by the number of times ...
... lower plate ; unclamp the upper plate , and bring the telescope to bear on C ; the vernier will show twice the angle A B C. We may repeat this operation at pleasure , the last reading of the vernier being divided by the number of times ...
Page 69
... lower plate , bring the vernier to zero , the tele- scope will be parallel to A B ; reverse the telescope on its axis , and set a stake at D. Case 2. When B is not accessible from C , Plant stakes at A , B , C , also Find , B C E at E ...
... lower plate , bring the vernier to zero , the tele- scope will be parallel to A B ; reverse the telescope on its axis , and set a stake at D. Case 2. When B is not accessible from C , Plant stakes at A , B , C , also Find , B C E at E ...
Page 73
... lower plate to the tripod , bring the telescope in its direct position on the next sta- tion , the vernier will perform the additions and subtractions of the angles of deflection ; conse- quently , when we arrive at any station when the ...
... lower plate to the tripod , bring the telescope in its direct position on the next sta- tion , the vernier will perform the additions and subtractions of the angles of deflection ; conse- quently , when we arrive at any station when 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.