An elementary treatise on optics / by I.W. Jackson.

  • Jackson, I. W. (Isaac Wilber), 1804-1877.
Date:
1867
Catalogue details

Licence: Public Domain Mark

Credit: An elementary treatise on optics / by I.W. Jackson. Source: Wellcome Collection.

Provider: This material has been provided by the Francis A. Countway Library of Medicine, through the Medical Heritage Library. The original may be consulted at the Francis A. Countway Library of Medicine, Harvard Medical School.

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    surface at the limiting angle ; and that all rays which fall in the angle AIN will emerge, while those which fall in the angle NIS will suffer total reflection. .• §3. Let G<L. [Fig. 37.] ' In this case, a little consideration renders it evi- dent that all the rays incident in the angle AIN will emerge, and some also of those incident in the angle NIS. • 48. Of the angle of deviation, and its minimum value. When the condition of emergence is fulfilled, the rays pass through the second surface, and undergo a greater or less change of direction, depending upon the angle of incidence, the index of refraction between air and glass, and the refracting angle of the prism. ASA' [Fig. 38] being, as before, a principal sec- tion of the prism, LI a ray incident in the section, II' and 10 'the corresponding transmitted and emergent rays, and 0 the place of the eye; let L'O be drawn so that, produced, it would pass through the point of the luminous object from which the ray LI proceeds; and let the distance of the object be so great, compared with the distance between the eye and the prism, that L'O may be considered parallel to LI; then, the change of direction which the light undergoes is evidently measured by the angle MOO or its equal O'OL'. The angle MOO is called the deviation. The point 0 is supposed to