The practical astronomer : comprising illustrations of light and colours, practical descriptions of all kinds of telescopes, the use of the equatorial-transit, circular, and other astronomical instruments, a particular account of the Earl of Rosse's large telescopes, and other topics connected with astronomy (1845)
Dick, Thomas, 1774-1857 · London : Seeley, Burnside, and Seeley · leaf 68
ong in the directionCE, which is called the refracted ray. Let theline FG be drawn perpendicular to the surface ofthe water in C, then it is evident that the ray BC,in passing out of air, a rare medium, into a densemedium, as water, is refracted into a ray CE whichis nearer to the perpendicular CG… … I G E PI figure 2. The same thing may be otherwise illustrated asfollows :—suppose a hole made in one of the sidesof the vessel as at a, and a lighted candle placedwithin two or three feet of it, when empty, so thatits flame may be at L, a ray of light proceed-ing from it will pass through the hole…
Astronomy · Astronomical instruments · Telescopes
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