A Manual for Practical Surveyors: Containing Methods Indispensably Necessary for Actual Field Operations |
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Page 11
... course . In the same manner examine various divisions round the com- pass box , the coincidence of the opposite ends of the needle , with the same degree , is a proof of its being correct . If it be a nonius compass , the nonius may be ...
... course . In the same manner examine various divisions round the com- pass box , the coincidence of the opposite ends of the needle , with the same degree , is a proof of its being correct . If it be a nonius compass , the nonius may be ...
Page 12
... course as formerly , unless the compasses , by which the bearings were taken , differ in other particulars . Another reason for preferring the nonius compass is , that we may run a line to minutes , by setting the needle to the whole ...
... course as formerly , unless the compasses , by which the bearings were taken , differ in other particulars . Another reason for preferring the nonius compass is , that we may run a line to minutes , by setting the needle to the whole ...
Page 14
... course as at the last station , and clamp the nonius plate ; a course may then be taken in any direc- tion with the needle , as correctly as if free from the effects of local attraction . The following description of an instrument for ...
... course as at the last station , and clamp the nonius plate ; a course may then be taken in any direc- tion with the needle , as correctly as if free from the effects of local attraction . The following description of an instrument for ...
Page 20
... courses shown by the needle , other- wise great and perplexing errors may be intro- duced . The surveyor should be furnished with tables of sines , as far as 20 ° extending to four decimals at least ; nat . tangents as far as 10 ° , and ...
... courses shown by the needle , other- wise great and perplexing errors may be intro- duced . The surveyor should be furnished with tables of sines , as far as 20 ° extending to four decimals at least ; nat . tangents as far as 10 ° , and ...
Page 25
... course of A B and run to C , and from thence to D , and so on as far as required . When it is required to run the line accurately , proceed thus : Plant the instrument at B , and having adjusted it , bring the sights to bear on the back ...
... course of A B and run to C , and from thence to D , and so on as far as required . When it is required to run the line accurately , proceed thus : Plant the instrument at B , and having adjusted it , bring the sights to bear on the back ...
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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.