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angle of incidence angle of refraction apparent magnitude appear axes axis of double centre chromatic coincide colour concave consequently convergent power convex lens cornea corresponding crown glass crystal crystalline diameter diminished direction disc distance distant objects distinct vision diverging double refraction effect equal extraordinary pencil extraordinary ray extreme focal length foci formed glass greater homogeneous light humour illuminated inch incident ray increased index of refraction intensity lenses less luminous point manner medium motion number of rays observer opaque optic axis ordinary pencil ordinary ray parallel rays pencil of rays perception perpendicular phenomena placed plane of polarisation plate position principal focus prism produced pupil radius reflected rays reflector refracting power refrangibility rendered represented in Jig retina right angles screen seen Sir David Brewster solar light space spectrum spherical aberration spherical reflector supposed surface tourmaline transmitted transparent tube violet vitreous humour yellow
Pagina viii - The perspicuity of the original has been retained, and chapters which had become obsolete, have been replaced by others of more modern character. The explanations throughout are studiously popular, and care has been taken to show the application of the various branches of physics to the industrial arts, and to the practical business of life.
Pagina 259 - And looks around in fear and doubt. But soon, the prospect clearing, By cloudless starlight on he treads, And thinks no lamp so cheering As that light which Heaven sheds.
Pagina 67 - When a ray of light passes from a rarer into a denser medium, it is bent towards the perpendicular, and from a denser into a rarer from the perpendicular, which is by no means generally true.
Pagina 276 - ... then if we allow the light of the sun, or the light of a candle, to act strongly upon the right eye, without affecting the left, which may be easily protected from its influence, the left hand strip of paper will be seen of a bright green colour, and the right hand strip of a red colour.
Pagina 309 - All kinds of yellows and blues, except sky-blue, he could discern with great nicety. His father, his maternal uncle, one of his sisters, and her two sons, had all the same defect. A tailor at Plymouth, whose case is described by Mr.
Pagina 424 - He found that, in order to produce perfectly beautiful and symmetrical forms, three conditions were necessary. 1. That the reflectors should be placed at an angle, which was an even or an odd aliquot part of a circle, when the object was regular, and wholly included in the aperture ; or the even aliquot part of a circle when the object was irregular.
Pagina 173 - Young, — a theory which, if not founded in nature, is certainly one of the happiest fictions that the genius of man has yet invented to group together natural phenomena, as well as the most fortunate in the support it has unexpectedly received from whole classes of new phenomena, which at their first discovery seemed in irreconcileable opposition to it.
Pagina 182 - A A' and B B', along which the rays grazing the edge of the opaque body would have proceeded, the two systems of undulation will intersect each other and produce the phenomena of interference.