An Account of the Operations Carried on for Accomplishing a Trigonometrical Survey of England and Wales: From the Commencement, in the Year 1784, to the End of the Year 1796, Volume 2W. Bulmer and Company, 1801 |
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Page 19
... wire was let fall from the register head , having a plummet , under the point of which a small dot was made , on a stake driven firmly into the ground . The great theodolite was then placed over the stake , and the instrument accurately ...
... wire was let fall from the register head , having a plummet , under the point of which a small dot was made , on a stake driven firmly into the ground . The great theodolite was then placed over the stake , and the instrument accurately ...
Page 20
... wires ; after which , a pin was moved on the surface of the peg , as directed by a person looking through the telescope , till it came to that point at which it bisected the angle formed by the cross wires . The measurement was then ...
... wires ; after which , a pin was moved on the surface of the peg , as directed by a person looking through the telescope , till it came to that point at which it bisected the angle formed by the cross wires . The measurement was then ...
Page 182
... wire , and so continue to do , till it was elevated 10 ′ , 45 ′′ above its first apparent situation ; it then remained stationary , and as night drew on , the object became indistinct . The follow- ing evening , I observed the ...
... wire , and so continue to do , till it was elevated 10 ′ , 45 ′′ above its first apparent situation ; it then remained stationary , and as night drew on , the object became indistinct . The follow- ing evening , I observed the ...
Page
... Wires Particulars relating to the Operations of the Year 1802 Particulars relating to the Measurement of a new Base Line on Misterton Carr Angles of the great Triangles observed in the Years 1800 , 25 26 28 30 38 1801 40 Reduction of ...
... Wires Particulars relating to the Operations of the Year 1802 Particulars relating to the Measurement of a new Base Line on Misterton Carr Angles of the great Triangles observed in the Years 1800 , 25 26 28 30 38 1801 40 Reduction of ...
Page
... Wires in the Focus of the Object and Eye - glasses from the true Line of Collimation Amplitudes of the celestial Arc , comprehended by the Stations Dunnose and Clifton Amplitudes of the celestial Arc , comprehended by the Stations ...
... Wires in the Focus of the Object and Eye - glasses from the true Line of Collimation Amplitudes of the celestial Arc , comprehended by the Stations Dunnose and Clifton Amplitudes of the celestial Arc , comprehended by the Stations ...
Common terms and phrases
Agnes Beacon Amplitude of arc Angles corrected Arbury Hill arch Ash Beacon axis azimuth Bardon Hill Beacon Hill Black Bodmin Bow Brickhill Bradley Knoll Brill Broadway Beacon Bull Barrow Butterton Cadon Barrow Carraton Hill Clifton Corley Cygni depr distance at Dunnose Ditto Dover Court Draconis Dundon Beacon Dundry Epwell feet Flagstaff Frierning Gravesend Gringley Hadleigh Halstow Hatfield Broad Oak Heath Heathersedge Hensbarrow Herculis Highbeech Highclere Kinsworth Langdon Hill Lansdown Lavenham length Lidlington Lillyhoe Limb Line of collimation Lugshorn Corner Mean Mendip Hills Moor Lynch Names of stations Nuffield Obelisk Observatory Observed angles Observed Zenith Distance Orpit Peldon perpendicular Pilsden Plate plumb-line Point Quainton Rayleigh refr Rippin Tor Rushmere screw Scutchamfly Severndroog Tower Sheppey Shotover Hill Signal Staff Southweald Spheri Spire Steeple Steeple Danbury Stoke Stow telescope Tillingham Trevose Head triangles Triptree Wendover Westbury White Horse Hill Whiteham Hill Windmill Zenith dist Zenith distance Zenith Sector
Popular passages
Page 103 - Head, for determining the length of a degree of a great circle perpendicular to the meridian. The truth of the deduction drawn from those observations rests on their accuracy; and it can scarcely be deemed presumptuous to assert, that an error of more than 1" cannot have existed in either of the angles.
Page 102 - ... deflection existed at Dunnose; as the deviation of it towards the north, from a deficiency of matter towards the channel, would tend to diminish the inequality between the lengths of the two degrees. This will be evident, on consideration. I am therefore disposed to believe that the plumb-line waá drawn towards the south, from the action of matter, both at the northern extremity of the arc and at Arbury Hill, but more particularly at the firstmentioned station.
Page 189 - An Account of the Measurement of an Arc of the Meridian, extending from Dunnose, in the Isle of Wight, Latitude 50° 37
Page 101 - The length of the degree at the middle point (51° 3.5' 18") between the southern extremity of the arc and Arbury Hill, is 60864 fathoms; which is greater than the above, and exceeds it by 44 fathoms. But this degree, admitting the earth to be an ellipsoid, with the ratio of its axes as 229 to 230, should be about 10 fathoms less. If the measurement of the...
Page 101 - From this measurement it appears, that the length of a degree on the meridian, in latitude 52° 2' 20", is 60820 fathoms. This conclusion is deduced from the supposition of the whole arc subtending an angle of 2° 50' 23",38 in the heavens, and a distance of 1036337 feet on the surface of the earth. The length of the degree at the middle point (51° 35' 18") between the southern extremity of the arc and Arbury Hill, is 60864.
Page 102 - ... of two stars, north and south of the zenith, at the greatest distances my arc would admit of. But, to return, if there be an error in the amplitude of the total arc, from a deflection of the plumb-line at either of the stations, it is not probable that any such deflection existed at Dunnose; as the deviation of it towards the north, from a deficiency of matter towards the channel, would tend to diminish the inequality between the lengths of the two degrees. This will be evident, on consideration....
Page 189 - London: / Published by W. Faden, Geographer to His / Majesty, and to His Royal Highness the Prince / of Wales, Charing Cross.
Page 102 - Arbury Hill, but more particularly at the firstmentioned station. If this were partly the case, and both Dunnose and Arbury Hill were free from any such prevailing cause, the total arc must be too great, if taken at 2° 50' 23",38, by about 8", nearly answering to 2" on each degree. A deviation of 8" from the true vertical, is a large quantity; nor can the cause of it be assigned, unless it be also supposed, that the matter producing that deflection extends in a southern direction beyond Arbury Hill....
Page 102 - ... consideration. I am, therefore, disposed to believe, that the plumb line was drawn towards the south from the action of matter, both at the north extremity of the arc and at Arbury Hillt, but more particularly at the first. If this were partly the case, and both Dunnose and Arbury Hill were free from such prevailing cause, the total arc must be too great if taken at 2° 50' 23",38, by about 8", nearly answering to 2