A Treatise on Optics |
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Page 2
... portion of a luminous surface , in no direction perceptibly extended : and so by a luminous line we may understand such a surface per- ceptibly extended in one direction only . We shall regard them simply as a mathematical point and a ...
... portion of a luminous surface , in no direction perceptibly extended : and so by a luminous line we may understand such a surface per- ceptibly extended in one direction only . We shall regard them simply as a mathematical point and a ...
Page 3
... portion of it is scattered or dispersed over the surface and makes the surface visible ; another portion is in general reflected in the first medium ( according to a law which will presently be stated ) - and in certain cases ( as when ...
... portion of it is scattered or dispersed over the surface and makes the surface visible ; another portion is in general reflected in the first medium ( according to a law which will presently be stated ) - and in certain cases ( as when ...
Page 29
... portion of it by the medium , yet from other causes the illumination at any point of a surface exposed to the light is different in different positions and at different distances from the surface . 38. Def . The illumination at any ...
... portion of it by the medium , yet from other causes the illumination at any point of a surface exposed to the light is different in different positions and at different distances from the surface . 38. Def . The illumination at any ...
Page 30
... portion of the curved surface contiguous to a given point on it , as coincident appreciably with the tangent plane to the surface at the point considered . 41. It is found by experiment that luminous surfaces appear to be of the same ...
... portion of the curved surface contiguous to a given point on it , as coincident appreciably with the tangent plane to the surface at the point considered . 41. It is found by experiment that luminous surfaces appear to be of the same ...
Page 34
... portion of the paper EF or FG . The instru- ment is then to be moved nearer to one or the other , till the paper on either side of the division F appears equally illu- minated . To judge of this it should be viewed through a tube ...
... portion of the paper EF or FG . The instru- ment is then to be moved nearer to one or the other , till the paper on either side of the division F appears equally illu- minated . To judge of this it should be viewed through a tube ...
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Common terms and phrases
aberration achromatism angle of incidence axis QA bright centre circle of least cloth coincides colours concave converge convex lens cos² Crown 8vo cuts the axis determine deviation direct pencil distance emergent equation excentrical eye-glass eye-piece Fcap fixed lines focal length geometrical focus Hence illumination image formed incident directly incident pencil index of refraction intersection lenses luminous point magnifying power medium mirror object object-glass parallel rays passes pencil of light pencil of parallel pencil of rays pencil whose axis perpendicular plane surface point of incidence position primary plane principal focus principal plane prism radii radius rays incident reflected or refracted reflected pencil reflexion or refraction refracted rays refracting angle refracting surface refractive index retina shew small oblique pencil small pencil spectrum sphere spherical reflector spherical surface supposed telescope thin lens v₁ v₂ αμ аф
Popular passages
Page 305 - Eumenides. The Greek Text with English Notes, and an Introduction, containing an Analysis of Miiller's Dissertations.