A Manual for Practical Surveyors: Containing Methods Indispensably Necessary for Actual Field Operations |
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Page 17
... observation , and directing one of the kerfs to an object ; a stake set in the direction of the other kerf will be at right angles with a line joining the cross , and the object observed . The Graphometer , or Semicircle , is also a ...
... observation , and directing one of the kerfs to an object ; a stake set in the direction of the other kerf will be at right angles with a line joining the cross , and the object observed . The Graphometer , or Semicircle , is also a ...
Page 31
... observation , however carefully made . It is best to repeat the measure of an angle , that the vernier may pass over ... observations . PROPOSITION 4 . Random Lines . To run a right line between two given points , when several ...
... observation , however carefully made . It is best to repeat the measure of an angle , that the vernier may pass over ... observations . PROPOSITION 4 . Random Lines . To run a right line between two given points , when several ...
Page 40
... by which it may be retraced by the circumferenter . Or place the transit at the beginning of the line , and adjust it for observation ; set the vernier to zero , and bring the telescope to bear on a 40 A MANUAL FOR SURVEYORS .
... by which it may be retraced by the circumferenter . Or place the transit at the beginning of the line , and adjust it for observation ; set the vernier to zero , and bring the telescope to bear on a 40 A MANUAL FOR SURVEYORS .
Page 59
... observations of this kind would enable him to ascertain the rate of increase or de- crease of the variation of the magnetic needle ; and would be highly valued by those who may be investigating this perplexing subject . Case 7. When the ...
... observations of this kind would enable him to ascertain the rate of increase or de- crease of the variation of the magnetic needle ; and would be highly valued by those who may be investigating this perplexing subject . Case 7. When the ...
Page 71
... Observe the an- d E D A B G F H gles B F G and F G B , the complements of which are F B C and G B C. The sum of these comple- ments is FB G. As the angle FB G , in degrees or minutes , Is to the angle F B C in the same measure , So is ...
... Observe the an- d E D A B G F H gles B F G and F G B , the complements of which are F B C and G B C. The sum of these comple- ments is FB G. As the angle FB G , in degrees or minutes , Is to the angle F B C in the same measure , So is ...
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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.