An Account of the Operations Carried Out for Accomplishing a Trigonometrical Survey of England and Wales: From the Commencement, in the Year 1784, to the End of the Year 1796, Begun Under the Direction of Royal Society, and Continued by Order of the Honourable Board of Ordance ; First Published In, and Revised From, the Philosophical Transactions, Volume 2W. Bulmer and Company, 1801 |
From inside the book
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Page 19
... adjusted over the dot . A diaphragm , whose aperture was an inch , was then put over the object - glass of the transit telescope , which was afterwards directed towards the staff at Lugshorn Corner , and then moved round , till it ...
... adjusted over the dot . A diaphragm , whose aperture was an inch , was then put over the object - glass of the transit telescope , which was afterwards directed towards the staff at Lugshorn Corner , and then moved round , till it ...
Page 102
... adjusted by plumb - lines or levels , are liable . In determining differences of longitude through these means , the direction in which any lateral attraction must act , to produce a maximum of error , is at right angles to the meri ...
... adjusted by plumb - lines or levels , are liable . In determining differences of longitude through these means , the direction in which any lateral attraction must act , to produce a maximum of error , is at right angles to the meri ...
Page 13
... adjustment by the coincidences of lines should have the preference . The first is undoubtedly the most expeditious method ; but seems at the same time to be liable to this very objectionable circumstance , that the probable errors fall ...
... adjustment by the coincidences of lines should have the preference . The first is undoubtedly the most expeditious method ; but seems at the same time to be liable to this very objectionable circumstance , that the probable errors fall ...
Page 15
... adjusted state , al- ways rests entirely on the surfaces of the two stands that support its extremities . But when the rod is to be raised from the stands , then the milled - headed screws , projecting above the upper sur- face , and ...
... adjusted state , al- ways rests entirely on the surfaces of the two stands that support its extremities . But when the rod is to be raised from the stands , then the milled - headed screws , projecting above the upper sur- face , and ...
Page 18
... adjustment of the lips of the bell - metal tip- pings , which extend exactly one inch and a half beyond the ivory lines , so as to make the total length of the rod 243 inches , it is to be observed , that they terminate in flat curves ...
... adjustment of the lips of the bell - metal tip- pings , which extend exactly one inch and a half beyond the ivory lines , so as to make the total length of the rod 243 inches , it is to be observed , that they terminate in flat curves ...
Contents
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Common terms and phrases
Allington Knoll Angles corrected Angles observed Ann's Hill Arbury Hill axis Banstead base Beachy Head Beacon Hill Black Botley Hill Bow Brickhill Bradley Knoll brass Brill Bull Barrow Butser Hill Butterton Carraton Hill Castle chain Chanctonbury Ring Church computed Crowborough Beacon deal rods Dean Hill degree depr distance Ditchling Beacon Dover Dumpdon Dundry Dunnose elev Epwell Fairlight feet Flagstaff glass rods Goudhurst ground Hampton Poorhouse Hanger Hill Hensbarrow Beacon Highclere Hind Head Hounslow Heath hypothenuses inches instrument intersected objects Karnbonellis Karnminnis King's Arbour Kinsworth Kit Hill Lansallos Leith Hill length Lidlington Light-house Maker Heights means measurement Mendip Meridian of Greenwich micrometer Moor Lynch Motteston Names of stations Nine Barrow Observed angles operation perpendicular Pertinney pickets Pilsden placed refraction Rippin Tor Rook's Hill screws Severndroog Castle Severndroog Tower Shooter's Hill side Spire staff Steeple telescope Tenterden triangles Waldershare Wendover White Horse Hill Windmill Wingreen wire
Popular passages
Page 2 - ... having been carried out with instruments of the common, or even inferior kind, and the sum allowed for it being inadequate to the execution of so great a design in the best manner, it is rather to be considered as a magnificent military sketch, than a very accurate map of a country...
Page 1 - Accurate surveys of a country are universally admitted to be works of great public utility, as affording the surest foundation for almost every kind of internal improvement in time of peace, and the best means of forming judicious plans of defence against the invasions of an enemy in time of war ; in which last circumstance, their importance usually becomes the most apparent.
Page 3 - on the conclusion of the peace of 1763 it came for the first time under the consideration of Government to make a general survey of the whole island at public cost...
Page 175 - BA, the sum of the two refractions ; hence, supposing half that sum to be the true refraction, we have the following rule when the objects are reciprocally depressed. Subtract the sum of the two depressions from the contained arc, and half the remainder is the mean refraction : — If one of the points B, instead of being depressed be elevated, suppose to the point g, the angle of elevation being gA.D, then * " Trigonometrical Survey,
Page 89 - An account of the trigonometrical operation, whereby the distance between the meridians of the Royal Observatories of Greenwich and Paris has been determined.
Page 2 - The rise and progress of the rebellion which broke out in the Highlands of Scotland in 1745, and which was finally suppressed by His Royal Highness the Duke of Cumberland at the battle of Culloden in the following year, convinced the Government of what infinite importance it would be to the State that a country, so very inaccessible by nature, should be thoroughly explored and laid open, by establishing military posts in its inmost recesses, and carrying roads of communication to its remoter parts.
Page 101 - Head ; and the length of a degree of a great circle, perpendicular to the meridian, in latitude 50° 41 . Section VI.
Page 2 - Assistant-Quarter-Master, it fell to my lot to begin, and afterwards to have a considerable share in, the execution of that map ; which being undertaken under the auspices of the Duke of Cumberland, and meant at first to be confined to the Highlands only, was nevertheless at last extended to the Lowlands...
Page xiii - An Account of the Measurement of an Arc of the Meridian, extending from Dunnose, in the Isle of Wight, Latitude 50° 37
Page 4 - ... of the most remarkable steeples, and other places, in and about the Capital, with regard to each other, and the Royal Observatory at Greenwich.