Items related to A text-book of medical physics; for the use of students...
Synopsis
This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1885 Excerpt: ...its interior. In the Lieberkiihn objective for microscopes, the glass objective is placed in the pole of a reflecting mirror, opaque objects are thus subjected to a more brilliant illumination (584). In reflecting telescopes concave mirrors are employed to produce images of celestial and terrestrial objects. These are also called catoptric telescopes. Various forms have been constructed. In the Herschelian telescope the reflector is set at a slight angle to the tube, and the image is produced at one side near the mouth, and there viewed directly by the eye of the observer. In the Newtonian rejiector it is set at right angles to the tube. In the axis of this near its mouth, a plane mirror reflects the converging beam to one side whence it passes through an aperture and is viewed by the eye. In the Gregorian form it is perforated through its pole; the rays, as in the Newtonian, are received upon a plane mirror, which is set parallel to the concave mirror; the converging beam is, therefore, sent back to the aperture in the centre of the concave mirror, and there viewed by the eye. By the process for silvering glass, telescope and other mirrors are now made of this substance and covered with pure silver. Accurate curvature, high reflecting power, and lightness are thereby obtained. CHAPTER XX. REFRACTION AND PRISMS. Refraction illustrated--Refraction power of different media--Laws of single refraction--Index of refraction--Critical angle. Total reflection--Atmospheric refraction and mirage--Media with parallel surfaces--The prism--Track of ray in prism. Angle of deviation--Minimum deviation--Reflecting prisms. 490. Refraction Illustrated.--Much of the light falling upon a surface is reflected; the quantity so disposed of is greater as the color of the body is l...
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