A Manual for Practical Surveyors: Containing Methods Indispensably Necessary for Actual Field Operations |
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Page 12
... variation between the present time , and that at which a survey was formerly made , set the nonius to this difference , the needle will show , on the face of the instrument , when the sights are set to the lines of survey , the same ...
... variation between the present time , and that at which a survey was formerly made , set the nonius to this difference , the needle will show , on the face of the instrument , when the sights are set to the lines of survey , the same ...
Page 39
... variation or correction of the course , Which , being applied to the given bearing , will give the present bearing of the line . Then set the instrument at the place of begin- ning , and run the line by its present bearing . This method ...
... variation or correction of the course , Which , being applied to the given bearing , will give the present bearing of the line . Then set the instrument at the place of begin- ning , and run the line by its present bearing . This method ...
Page 41
... variation between the present time , and the time a line was formerly run ; all the lines of survey run at that time may be retraced , by setting the needle to the given bearings of the lines . This cuts off the pos- sibility of errors ...
... variation between the present time , and the time a line was formerly run ; all the lines of survey run at that time may be retraced , by setting the needle to the given bearings of the lines . This cuts off the pos- sibility of errors ...
Page 56
... variation is obtained , which being applied to the former bearings , gives the present bearings of the lines . The lines may then be run out . This may be done with both adjacent tracts of land , and a mean of the results taken . A ...
... variation is obtained , which being applied to the former bearings , gives the present bearings of the lines . The lines may then be run out . This may be done with both adjacent tracts of land , and a mean of the results taken . A ...
Page 57
... variation in the interval of time which applied to the given bearing of the line to be run , we shall have its present bearing . The variation at West Chester , in 1845 , is 4 ° 2 ′ W. The variation of the magnetic needle in declina ...
... variation in the interval of time which applied to the given bearing of the line to be run , we shall have its present bearing . The variation at West Chester , in 1845 , is 4 ° 2 ′ W. The variation of the magnetic needle in declina ...
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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.