Page:Popular Science Monthly Volume 11.djvu/371

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THE ZODIACAL LIGHT.

In this diagram, the sun's rays being S', S", etc., BO, FO, etc. will be the reflected rays; and the several angles between these lines of incidence and reflection, together with the number of rays reflected

PSM V11 D371 Nebulous ring with earth at its centre.jpg
Nebulous Ring, with the Earth for its Centre.

|[The relative proportions of the earth and the ring, and also its distance, are of course not given in this diagram with any effort at certainty; the upward extent of the ring is probably far greater than can be here represented. The diagram is, however, sufficiently correct for our present purposes of elucidation.]

to the eye, out of every 1,000 incident rays, according to Bouguer, are in the following table:

ANGLE Rays reflected from
Smooth Water.
Rays reflected from
Plate-glass not quick-
silvered.
S’ B0 161° 343 422
S'' F0 146° 184 270
S''' D0 131° 101 162
S'''' H0 116° 59 105
S''''', at midnight 90° 18 25
S'''''', C0 67° 18 25