An Elementary Treatise on Geometrical OpticsUniversity Press, 1888 - 212 pagine |
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An Elementary Treatise on Geometrical Optics (Classic Reprint) R. S. Heath Anteprima non disponibile - 2016 |
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achromatic angle of incidence aperture apparent magnitude astronomical telescope axis B₁ bright point called caustic centre circle concave concave lens conjugate foci conjugate points converge convex lens denote direction distinct vision emerge parallel emergent ray equal equation extreme pencils eye-glass eye-lens eye-piece field of view final image focal length glass Hence illuminated inches incident ray inclined instrument lenses linear magnitudes luminous point magnifying power meet minimum deviation nodal points normal number of images object object-glass object-mirror orthotomic pencil perpendicular placed plane mirror point Q position principal focus principal plane principal points prism Prove pupil radii radius ray of light ray passes rays diverging reflected rays refracting angle refracting surface refractive index respectively retina right angles seen small mirror spectrum sphere spherical surface subtended suppose tangent triangles vertex
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Pagina 104 - The space between the cornea and the crystalline lens is filled with a transparent fluid resembling water, and thence termed the aqueous humour. The space between the crystalline lens and the retina is filled with another transparent fluid, somewhat more viscous than the former, and called the vitreous humour. These two humours, like the crystalline lens, are contained in transparent membranous capsules of great delicacy. In their refractive indices the aqueous and vitreous humours differ very little...
Pagina 4 - Let f(6) be the intensity of emission per unit area in a direction making an angle 0 with the normal to the element ; then the whole amount of light transmitted to the eye when the element is inclined to the line of sight at an angle 6 is to sec 9 .f(0).
Pagina 37 - The number of images is limited ; for when any one of the images falls on the arc ab, between the mirrors produced, it lies behind both mirrors, and therefore no further reflexion takes place. If the image...
Pagina 83 - The gradual removal of these suspicions at length led me to the experimentum crucis, which was this. I took two boards, and placed one of them close behind the prism at the window...
Pagina 127 - Doublet. It was suggested by an inverted Huyghens' eye-piece, to be described presently. It consists of two planoconvex lenses whose focal lengths are in the proportion of 1 : 3, the plane surfaces being turned towards the object, and the lens of shorter focal length being placed next the object. The distance between the lenses can be adjusted to suit different eyes, but is usually \ of the shorter focal length.
Pagina 15 - ... be a cylindrical pencil parallel to the axis and of the same diameter as the incident pencil.
Pagina 104 - These concave lenses will neutralize the effect of the lens c to a certain extent; but not so much as if their refractive indices were as high as that of c. The focal length of the lens may be found by experiment, and its shape being known, its • so-called total refractive index may be found; that is, the refracting index which the lens would possess, were it homogeneous. From what has been previously said, it follows that this total refractive index is greater than that of the nucleus. The increase...
Pagina 33 - ... table, find the angle of each prism in order that a ray refracted through each of them in a principal plane may describe a regular polygon. Show that the distance of the point of incidence of such a ray on each prism from the edge of the prism, bears to the distance of each edge from the common centre the ratio of fjf — 2/j, cos — + 1 : /* + 1.
Pagina 123 - CPM, that is as the apparent magnitude of the line NO seen from P, to the true. And therefore, by turning the figure round the axis OP, the quantity of refracted rays which fill the pupil is to the quantity of unrefracted rays which would fill it (as the apparent magnitude of any surface at 0 seen from P, to the true; or as the apparent magnitude of any surface at P seen from 0 to the true ; and consequently) as the apparent magnitude of the least surface, or physical point P, to the true ; that...
Pagina 42 - ... the instrument is much simplified and the labor of making measurements is greatly reduced, since, when the refracted image of the slit coincides with the slit, the position of minimum deviation is attained.