A Treatise on Mine-surveying |
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Page 26
... The compass has only a north and south line marked , and round its raised edge a double ruler revolves . The wooden plate has several concentric circular When in use , depressions , filled with wax of 26 MINE - SURVEYING . CHAPTER III.
... The compass has only a north and south line marked , and round its raised edge a double ruler revolves . The wooden plate has several concentric circular When in use , depressions , filled with wax of 26 MINE - SURVEYING . CHAPTER III.
Page 27
... Edge of your Dial , that is , equally at both Ends ; or else you will miss in taking the true Point . Under Ground the Dial is guided by the String ; but above Ground the String is guided by the Dial . " Even in the middle of the last ...
... Edge of your Dial , that is , equally at both Ends ; or else you will miss in taking the true Point . Under Ground the Dial is guided by the String ; but above Ground the String is guided by the Dial . " Even in the middle of the last ...
Page 30
... edge . The surveyor should therefore examine both his watch and his hat before commencing a survey . Sometimes the needle persistently sticks to the under side of the glass . This is caused by the glass becoming electrified from rubbing ...
... edge . The surveyor should therefore examine both his watch and his hat before commencing a survey . Sometimes the needle persistently sticks to the under side of the glass . This is caused by the glass becoming electrified from rubbing ...
Page 33
... edge . A plumb - line was then suspended from the pin in the upper edge of the cover . This line coincided with the zero of the graduation when the sights were horizontal . On turning them upwards or downwards from that position , the ...
... edge . A plumb - line was then suspended from the pin in the upper edge of the cover . This line coincided with the zero of the graduation when the sights were horizontal . On turning them upwards or downwards from that position , the ...
Page 45
... edge , a portable instrument , Fig . 14 , termed a gnomon , is formed . This can be placed on a table or drawing - board in the open air , and used in the manner described . 2. Method of Corresponding Altitudes . - If a good theodolite ...
... edge , a portable instrument , Fig . 14 , termed a gnomon , is formed . This can be placed on a table or drawing - board in the open air , and used in the manner described . 2. Method of Corresponding Altitudes . - If a good theodolite ...
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Common terms and phrases
accuracy accurate adjusted back-sight base-line bearing bore-hole brass calculated centre chain City Guilds clamped clinometer coal colliery collimation colour compass compass-box contour lines cord corner cosec cotan cross-wires curve determined direction distance employed equal error fathoms feet fixed fore-sight glass graduated ground height hole horizontal circle inches inches in diameter inclination instrument intersection latitude length lode magnetic bearing magnetic meridian magnetic-needle marked means measured method metres mine-surveying miner's dial mines needle observations obtained offsets Ordnance Survey parallel parallel ruler perpendicular placed plane plate plotting plumb-bob plumb-line plummet position protractor represented right angles safety-lamp scale seam shaft side Silver King spirit-level square staff station station-line strike and dip surface surface-surveys survey tacheometer tacheometry taken tangent screw telescope theodolite transit-theodolite traverse triangle tripod tube underground vernier vernier-plate vertical angles wire yards zero