Geodesy |
Common terms and phrases
a₁ astronomical axis azimuth B₁ base line bisection C₁ calculation circle clock coefficients collimation corrections corresponding cos² deflection density determined difference of longitude earth ellipsoid equal equations of condition expressed feet figure Formentera formula gives gravity height horizontal inches Indian Kaliana length longitude mass mean measured meridian metre micrometer microscopes miles observed angles observed latitudes obtained oscillations P₁ P₂ pendulum plane curves prime vertical probable error quantities radius of curvature result Sca Fell semiaxes side sin² Slieve Donard sphere spherical excess spherical triangle spheroid squares star stations substitute Suppose surface telescope temperature theodolite tions toises transit instrument values vertical vibration w₁ x₁ zenith distance zero
Popular passages
Page 112 - A cos 6 = cos a cos c + sin a sin c cos B cos c = cos a cos 6 + sin a sin 6 cos C Law of Cosines for Angles cos A = — cos B...
Page 92 - ... so that the amount of matter in any vertical column drawn from the surface to a level surface below the crust is now, and ever has been, approximately the same in every part of the earth.
Page 60 - In the Figure of the Earth no other person has accomplished so much as Clairaut: and the subject remains at present substantially as he left it, though the form is different. The splendid analysis which Laplace supplied adorned, but did not really alter, the theory which started from the creative hands of Clairaut.
Page 7 - Je prévis que cet ancien étalon, fait assez grossièrement,. et d'ailleurs exposé aux chocs, aux injures de l'air, à la rouille, au contact de toutes les mesures qui y sont présentées, et à la malignité de tout mal-intentionné, ne...
Page 26 - An Account of the Measurement of two Sections of the Meridional Arc of India, bounded by the Parallels of 18° 3' 15", 24° 7' 11", 29a 30
Page 97 - Chauvenet's Practical Astronomies. The astronomic latitude of a point on the surface of the earth is the angle between the line of action of gravity at that station and the plane of the equator. It is measured on the celestial sphere along the meridian from the equator to the zenith. The astronomic longitude of a point on the surface of the earth is the angle between the meridian plane of that point and some...
Page 92 - ... and ocean beds has arisen from the mass having contracted unequally in becoming solid from a fluid state ; and that below the sea-level, under mountains and plains, there is a deficiency of matter, approximately equal in amount to the mass above the sea-level ; and that below oceanbeds there is an excess of matter approximately equal to the deficiency in the ocean when compared with rock ; so that...
Page 76 - It is not assumed that the strata were originally fluid; but it is assumed that the superficial stratum has the same form as if it were fluid and in relative equilibrium when rotating with uniform angular velocity. There is no limitation on the law by which the ellipticity varies from stratum to stratum, except that the ellipticity must be continuous, and at the surface must be such as would correspond to the relative equilibrium of a film of rotating fluid.
Page 291 - The longitude of the greater axis of the equator is 8° 15' west of Greenwich — a meridian passing through Ireland and Portugal and cutting off a portion of the north-west corner of Africa; in the opposite hemisphere this meridian cuts off the north-eastern corner of Asia and passes through the southern island of New Zealand. The meridian containing the smaller diameter of the equator passes through Ceylon on the one side of the earth and bisects North America on the other. This position of the...
Page 7 - ... ne serait guère propre à rectifier dans la suite la toise qui allait servir à la mesure de la Terre, et devenir l'original auquel les autres devraient être comparées. Il me parut donc très nécessaire, en emportant une toise bien vérifiée, d'en laisser à Paris une autre de même matière et de...